Question

if 20bs. of rice and 30lbs. of potatoes cost 26.60 and 30lbs of rice and 12lbs. potatoes cost 26.04 how much will 10lbs of rice and 50lbs. of potatoes cost. thhe cost of 10lbs of rice and 50lbs of potatoes is_____(simplify answer)

Answer 1

20r + 30p = 26.60...(multiply by 3)
30r + 12p = 26.04...(multiply by -2)
---------------------
60r + 90p = 79.80 (result of multiplying by 3)
-60r - 24p = - 52.08 (result of multiplying by -2)
-------------------add
66p = 27.72
p = 27.72/66
p = 0.42.....so potatoes cost 42 cents per lb

20r + 30p = 26.60
20r + 30(0.42) = 26.60
20r + 12.60 = 26.60
20r = 26.60 - 12.60
20r = 14
r = 14/20
r = 0.70....so rice costs 70 cents per lb

10(0.70) + 50(0.42) = 7 + 21 = $ 28 <== the cost of 10 lbs rice and 50 lbs potatoes