Question

Two numbers are in the ratio of $4:5$ if difference of their cubes is $61$. Find the numbers.

Answer 1

Let numbers are 4x and 5x

then,

$(5x{)}^3-(4x{)}^3=61$

$125x^3-64x^3=61$

$61x^3=61$

$x=1$

thus numbers are 4 and 5