A grocer has two kinds of candies, one selling for 90 cents a pound and the other for 40 cents a pound. How many pounds of each kind must he use to make 100 pounds worth 85 cents a pound?
Answers
Let the pounds of candles worth 90 cents be x which is sold .
Let the pounds of candles worth 40 cents be y which is sold .
Given in the question :
There are 100 pounds sold .
Hence the sum of the sold pounds will be 100 .
x + y = 100 ------(1)
The total sum of the money will be 100 × 85 = 8500 .
The money after selling the x pounds = 90 x
The money after selling the y pounds = 40 y .
The sum of 90 x and 40 y will be 8500 .
90 x + 40 y = 8500 -----(2)
Multiply equation (1) with 90 :
90 x + 90 y = 9000 ------(3)
Subtract equation (3) from (2) :
⇒ 40 y - 90 y = 8500 - 9000
⇒ - 50 y = - 500
⇒ y = - 500 / 50
⇒ y = 10
Put this value in (1) :
⇒ x + 10 = 100
⇒ x = 100 - 10
⇒ x = 90
The number of 90 cents a pound should be 90 .
The number of 40 cents a pound should be 10 .
Answer:
Step-by-step explanation:
Given:
Candy x = 0.90 per pound
Candy y = 0.40 per pound
100 pounds * 0.85 per pound = 85
x + y = 100
0.90x + 0.40y = 85
x = 100 - y
0.90(100 - y) + 0.40y = 85
90 - 0.90y + 0.40y = 85
-0.50y = 85 - 90
y = -5 / -0.50
y = 10
x = 100 - y
x = 100 - 10
x = 90
0.90x + 0.40y = 85
0.90(90) + 0.40(10) = 85
81 + 4 = 85
85 = 85