Question

An alloy contains 26% of copper. What quantity of alloy is needed to get 260g of copper?

Answer 1

Hint: Here, the quantity of alloy is unknown, so we treat it as x and then we calculate 26% of copper in this unknown quantity x and proceed.

Complete step-by-step answer:
Let x be the quantity of alloy.
Then according to question:-
26% of alloy = 260 g
Here alloy is x-now, put x in the place of alloy.
26% of x = 260 g
Now, of change in x sign according to BODMAS,
26% x = 260 g.
After change % from, when remove y, then put 100 in the denominator of that number
\[\dfrac{{26}}{{100}} \times \dfrac{x}{1} = 260g\]
After cross-multiply the number,
$26x \times 1 = 260 \times 100g$
$26x = 260 \times 100g$
26 number that is multiply by variable x shift into other side and 26 number divided to right side
So $x = \dfrac{{260 \times 100}}{{26}}g$
x = 10\[ \times \]100 g
x = 1000g
Hence, the quantity of an alloy is 1000g.

Note: Calculate the percentage of the quantity appropriately and compare it with the unknown quantity.Also, make sure to write the appropriate unit associated with it.