Question

A 4-pound box of rice, which is a mixture of white rice and wild rice, sells for $1.80 per pound.
White rice sells for $0.75 per pound.
Wild rice sells for $2.25 per pound.
How many pounds of white rice are in the mixture?

-White rice = W
Wild ride= S
S+W=1.80
0.75w+2.25s=7.2
That is all i know what to do and i think the 7.2 is wrong i dont know

Answer 1

amount of white rice ---- x pounds
amount of wild rice ------4-x pounds
(no need for 2 variables)

.75x + 2.25(4-x) = 1.8(4)
.75x + 9 - 2.25x = 7.2
-1.5x = -1.8
x = 1.2

so we have 1.2 pounds of white rice and 2.8 pounds of wild rice

check:
1.2(.75) + 2.8(2.25) = 7.2
4(1.8) = 7.2
my answer is correct.

If the total is only 4 pounds, did it not seem totally illogical to have 7.2 pounds ??