Answer:
He used 6 bananas at .50 which cost $3.00
12 oranges at .75 which cost $9.00 and
3 papayas at $1.25 which cost $3.75
Explanation:
We can set up a system of equations using the information given.
b for banana, r for orange, p for papaya
b + r + p = 21. Also given r = 2b So substitute to simplify for calculating two unknowns:
b + 2b + p = 21 The number of items.
50b + 75(2b) +125p = 1575 The cost.
I multiplied everything by 100 to eliminate the decimals.
To solve by substituion, rewrite the first equation to get a value for p in terms of b
p = 21 - 3b
Substitute this value in the second equation and solve for b.
50b + 150b + 125(21–3b) = 1575
200b +2625 –375b = 1575 Subtract 2625 from both sides and combine the like terms:
–175b = 1575 –2625
–175b = –1050. Divide both sides by –175
b = 6
Substitute in the original equation to find the amount of each fruit:
b + r + p = 21
b = 6 bananas
r = 2b. 2(6) = 12 oranges. I used r so as not to mix up o with 0.
6 + 12 + p = 21
p = 21 –18
p = 3 papayas