uhm basically this is the part 2 of applications of percent quiz (GA connections academy)
108 is 36% of what number? write and solve a proportion to solve the problem
72 is what percent of 480? write and solve an equation to solve the problem
Explain how mental math can be used to estimate a 15% tip on a taxi ride that costs $23.25. Find the tip using that method
0.36/108 = 1/x
x = 108*1/0.36 = 300
480 x ?% = 72
?% = 72/480 = 15%
Check: 480 x 0.15 = 72
To solve the problem "108 is 36% of what number?", you can set up and solve a proportion. Let's say the unknown number is represented by "x".
The proportion can be set up as:
108 / x = 36 / 100
To solve the proportion, you can cross-multiply and solve for x:
108 * 100 = 36 * x
10,800 = 36x
Dividing both sides of the equation by 36 gives:
x = 10,800 / 36
x = 300
So, 108 is 36% of 300.
To solve the problem "72 is what percent of 480?", you can set up and solve an equation. Let's say the unknown percentage is represented by "p".
The equation can be set up as:
72 = p% * 480
To solve for p, you can divide both sides of the equation by 480:
72 / 480 = p%
Simplifying the left-hand side gives:
0.15 = p%
To convert the decimal to a percentage, you can multiply by 100:
0.15 * 100 = p%
p% = 15
So, 72 is 15% of 480.
To estimate a 15% tip on a taxi ride that costs $23.25 using mental math, you can calculate it as follows:
Step 1: Divide the cost by 10 to find 10% of the total:
$23.25 / 10 = $2.325
Step 2: Multiply the result from Step 1 by 1.5 to find 15% of the total:
$2.325 * 1.5 = $3.4875
Step 3: Round the result from Step 2 to the nearest whole number or appropriate amount for tipping (e.g., $3.50):
The estimated 15% tip is approximately $3.50.
To solve the first problem, let's use a proportion to find the number. The proportion is as follows:
108 / x = 36 / 100
To solve this proportion, cross-multiply and then solve for x:
108 * 100 = 36 * x
10,800 = 36x
Divide both sides by 36 to isolate x:
x = 300
So, 108 is 36% of 300.
Now, let's solve the second problem using an equation:
72 is what percent of 480? Let's represent "what percent" as "x".
We can set up the equation as follows:
72 = x/100 * 480
To solve for x, divide both sides of the equation by 480:
72/480 = x/100
0.15 = x/100
Now, cross-multiply:
0.15 * 100 = x
15 = x
Therefore, 72 is 15% of 480.
Now, let's talk about how to use mental math to estimate a 15% tip on a taxi ride that costs $23.25.
To find a 15% tip, you can multiply the cost by 0.15 since 15% is equal to 0.15 in decimal form.
Here's how you can estimate it mentally:
Step 1: Take 10% of $23.25 by moving the decimal point one place to the left: $2.325.
Step 2: Multiply the result (10% value) by 1.5 to approximate 15%.
$2.325 * 1.5 = $3.4875.
So, using mental math, you can estimate that a 15% tip on a taxi ride costing $23.25 is approximately $3.49.