Question

last week charlie had several rice cakes and 3 granola bars as snacks.the snacks contained a total of 800 calories.If each granola bar had 120 calories and each rice cake had 40 calories how many rice cakes did she have?

Answer 1

Charlie had rice cakes and 3 granola bars as snacks last week

Required is the number of rice cakes Charlie had the previous week

let number of granola bar be b

and

let number of rice cake be a

ax + by = z.............(1)

ax + 3y = z......... (1)

x =calories of rice cake = 40

a = number of rice cakes

z = Total number of calories snacks = 800

y = calories of granola bar = 120

40a + 3(120) = 800

40a = 800 - 360

40a = 440

40a/40 = 440/40

a = 11 rice cakes