Math Inequality: Doughnut Budget

by Andrew McMorgan 33 views

Hey guys! Ever found yourself staring at a doughnut case, trying to figure out how many of those fancy ones you can snag without blowing your budget? Well, today we're diving into a classic math problem that's totally relatable, especially when those Saturday morning cravings hit. We've got Marat here with a sweet $16 budget, and he's faced with a delicious dilemma: specialty doughnuts at $2 a pop and classic glazed ones at $1 each. Our mission, should we choose to accept it (and we totally should, because doughnuts!), is to figure out how to represent this situation mathematically using an inequality and then explore some tasty combinations. This isn't just about numbers; it's about making smart choices when faced with irresistible baked goods!

Setting Up the Inequality: The Math Behind the Munchies

Alright, let's get down to business with Marat's doughnut conundrum. The core of this problem is about inequalities, which are mathematical expressions that compare two values when they are not necessarily equal. In Marat's case, he can't spend more than $16; he can spend 16orless.Thisiswherethe"lessthanorequalto"symbol(16 or less. This is where the "less than or equal to" symbol (\leq$) comes into play. To build our inequality, we need to define our variables. Let's say 's' represents the number of specialty doughnuts Marat buys, and 'g' represents the number of glazed doughnuts he picks up. Since each specialty doughnut costs $2, the total cost for specialty doughnuts will be 2s2s. Similarly, since each glazed doughnut costs $1, the total cost for glazed doughnuts will be 1g1g (or just gg). The total cost of all the doughnuts Marat buys is the sum of these two amounts: 2s+g2s + g. Now, here's the crucial part: this total cost must be less than or equal to Marat's budget of $16. So, the inequality that perfectly describes this situation is: 2s+g≤162s + g \leq 16. This inequality is our mathematical blueprint, guiding us through every possible doughnut purchase Marat can make without breaking the bank. It's a concise way to capture all the possible combinations, ensuring Marat enjoys his breakfast without any financial frosting-related frowns. Remember, 's' and 'g' must also be non-negative integers (you can't buy half a doughnut, and you can't buy a negative number of them!), which is an important constraint in real-world problems like this.

Graphing the Possibilities: A Visual Feast of Doughnut Options

So, we've got our inequality: 2s+g≤162s + g \leq 16. But what does this actually look like? Graphing this inequality gives us a visual representation of all the possible combinations of specialty and glazed doughnuts Marat can buy. When we graph inequalities involving two variables, we typically use a coordinate plane. Let's put the number of specialty doughnuts (ss) on the horizontal axis (the x-axis) and the number of glazed doughnuts (gg) on the vertical axis (the y-axis). The line representing 2s+g=162s + g = 16 is our boundary. To find this line, we can find two points on it. If Marat buys 0 specialty doughnuts (s=0s=0), then g=16g = 16. So, one point is (0, 16). If he buys 8 specialty doughnuts (s=8s=8), then 2(8)+g=162(8) + g = 16, which means 16+g=1616 + g = 16, so g=0g = 0. Thus, another point is (8, 0). Connecting these points gives us the boundary line. Because our inequality is 2s+g≤162s + g \leq 16, we shade the region below this line. This shaded area represents all the pairs of (s,gs, g) that satisfy the inequality. However, we also have the constraint that s≥0s \geq 0 and g≥0g \geq 0, meaning we only consider the first quadrant of the graph. Furthermore, since Marat can only buy whole doughnuts, the actual solutions are the integer points (points with whole number coordinates) within the shaded region and on the boundary line. So, while the graph shows a continuous shaded area, the real-world solutions are discrete points. Imagine plotting each possible combination of whole doughnuts on this graph – each point within the shaded triangle (including the axes segments and the boundary line) represents a valid purchase. It's like a treasure map to deliciousness, showing every possible doughnut combo within budget! The slope of the boundary line is -2, which tells us that for every increase of one specialty doughnut, Marat has to give up two glazed doughnuts to stay within budget. This visual approach helps us grasp the trade-offs involved in choosing between the pricier specialty doughnuts and the more affordable glazed ones, making it easier to spot the optimal choices.

Two Possible Combinations: Delicious Decisions!

Now for the fun part – figuring out some actual doughnut combinations Marat can enjoy! Using our inequality 2s+g≤162s + g \leq 16, we just need to pick values for ss and gg that make the statement true. Remember, ss and gg must be whole numbers (0, 1, 2, etc.) and cannot be negative.

Combination 1: A Specialty Treat

Let's say Marat is feeling a bit fancy and wants to go for 3 specialty doughnuts. So, s=3s = 3. Plugging this into our inequality: 2(3)+g≤162(3) + g \leq 16. This simplifies to 6+g≤166 + g \leq 16. To find the maximum number of glazed doughnuts he can buy, we subtract 6 from both sides: g≤10g \leq 10. So, Marat can buy 3 specialty doughnuts and up to 10 glazed doughnuts. Let's pick a specific number, say he buys 7 glazed doughnuts (g=7g = 7). The total cost would be 2(3)+7=6+7=132(3) + 7 = 6 + 7 = 13. Since 13≤1613 \leq 16, this is a perfectly valid and delicious combination! He'd have $16 - $13 = $3 left over, which is great!

Combination 2: Glazed Goodness

What if Marat decides to load up on the classics? Let's say he buys 10 glazed doughnuts. So, g=10g = 10. Plugging this into our inequality: 2s+10≤162s + 10 \leq 16. Subtracting 10 from both sides gives us 2s≤62s \leq 6. Dividing by 2, we get s≤3s \leq 3. This means he can buy up to 3 specialty doughnuts. To keep it simple and ensure he stays within budget, let's say he buys 2 specialty doughnuts (s=2s = 2). The total cost would be 2(2)+10=4+10=142(2) + 10 = 4 + 10 = 14. Since 14≤1614 \leq 16, this combination also works! He'd have $16 - $14 = $2 left over. See guys, math can actually lead to more doughnuts!

These are just two examples, and there are many, many more! The beauty of the inequality and its graph is that they show us all the possibilities. Whether Marat wants a mix of fancy and plain, or leans heavily towards one type, he can use this math to make sure he gets the most doughnut enjoyment for his $16. Happy munching!