Question

A scout troop consists of 10 boys and 10 girls. The total weight of their backpacks is 600 pounds. All the boys have to carry backpacks that weigh the same amount. All the girls, too, must carry bags of equal weight, but the girls' backpacks are 1.5 times lighter than the boys' backpacks. How heavy is one boy's backpack?

Answer 1

36 lbs

Explanation:

let the weight of each boy's backpack be B and the weight of each girl's backpack be G.

Given that the total weight of all (i.e 10 boys' and 10 girls') backpacks equals 600 lbs, i.e.

10B + 10G = 600 (simplifying by dividing both sides by 10)

B + G = 60 ------- eq 1

Also given that a girl's backpack is 1.5 times LESS than a boy's backpack.

written another way, we can say that a boy's backpack is 1.5 times MORE than a girl's backpack, or:

B = 1.5G (rearranging)

B - 1.5G = 0 ------ eq 2

We can solve eq 1 and eq 2 by elimination,

(eq 1) - (eq 2)

(B + G) - (B - 1.5G) = 60 - 0

B + G - B + 1.5G = 60

G + 1.5G = 60

2.5G = 60 (divide both sides by 2.5)

G = 60 / 2.5

G = 24 lbs (substitute this into equation 1)

B + G = 60

B + 24 = 60

B = 60 - 24

B = 36 lbs