Question

A rectangle has a perimeter of 50 centimeters. If the width of the rectangle is 10 centimeters, what is its length? step by step on how you got answer. thank you

Answer 1

$Perimeter=2Length+2Width \\ P=2(L+W) \\ 50=2(L+10) \\ 25=L+10 \\ L=25-10 \\ \boxed{L=15cm}$

Answer 2

Ok,   so,, if the p=50, it means that  l+l+w+w=50. (l is length and w is width.)

In simpler form, 2xl+2xw=50. In this case, we know that the width is 10. So,

2xl + 2 x 10= 50
2 x l +20=50.
Now we subtract 20 on both sides to get l alone. 
 2 x l=30
length= 30 divided by 2, or 15
 :-)