15 is 16.66666 percent of 90.
Step-by-step explanation:

Swap the sides of the equation :
⤑ 
We want to remove the 17.56 first.
Since the original equation is 17.56 , we are going to use the opposite operation and subtract 17.56 from both sides :
⤑ 
Simplify. 17.56 - 17.56 = 0 on the left. 30.16 - 17.36 = 12.6 on the right.
⤑ 
Then, we need to think about how to remove the coefficient 5. Since the opposite of multiplication is division , I am going to divide both sides by 5.
⤑ 
Simplify. 5/5 = 1 on the left and 12.6/5 = 2.52 on the right. So, Our answer is x = 2.52.

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The length of a circumference: l=πD
l₁=π×5=5π
l₂=π×15=15π
Then l₂÷l₁=15π÷5π=3 and the answer is B)
16 - 7 is 9
9 x 2 is 18
His weekly allowance is 18
Me. Gregory's class has the greatest ratio of boys to students.