SOLUTION: Hi, i need help on my homework. They are word problems. 1. the length of a rectangle is 3 times the width. The perimeter is 40. What is the length and the width of the rectangle?

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Hi, i need help on my homework. They are word problems. 1. the length of a rectangle is 3 times the width. The perimeter is 40. What is the length and the width of the rectangle?       Log On


   

Question 945278: Hi, i need help on my homework. They are word problems.
1. the length of a rectangle is 3 times the width. The perimeter is 40. What is the length and the width of the rectangle?
2. the population of a gardens high school is 2500. If the number of males is 240 more than the number of females, how many males and females are there?
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

1.
if the length L of a rectangle is 3+times the width W, we have
L=3W
if the perimeter is 40=> 2%28L%2BW%29=40 ...substitute L from above
2%283W%2BW%29=40
%284W%29=20
W=20%2F4
W=5
go to L=3W, substitute 5 for W
L=3%2A5
L=15
so, the length is 15 and the width is 5

2.
the population of a gardens high school is 2500,
If the number of males is 240 more than the number of females, how many males and females are there?
let the number of males be m and the number of females f
we know that m%2Bf=2500...eq.1
we also know that m=f%2B240....eq.2 ...substitute it in eq.1
f%2B240%2Bf=2500...eq.1...solve for f

2f=2500-240
2f=2260
f=2260%2F2
highlight%28f=1130%29->the number of females
now find m=f%2B240
m=1130%2B240
highlight%28m=1370%29->the number of males