Question

an ore contains 14% copper. how many kilograms of the ore are required to get 77 kg of copper ? full procedure and with a shortcut plzz

Answer 1

let the total quantity of the ore
be'X' kg
so 12% of that ore is copper.
According to the question

(X*12)/100 =69
12X/100=69
3x/25=69
3x=69*25
3x=1725
x=1725/3
x=575kg

so, 575 kg ore is required to get 69kg of copper

Answer 2

Let the required ore =x kg.

and, ore contain 14% of copper (given)
so, According to question

14% of ore = 77kg of copper
x × 14/100 = 77
=> x= 77× 100/14
=> x= 550kg