Question

two spheres having the ratio of their densities 2:5 and masses in 6:5 respectively.find the ratio of their volumes

Answer 1

Let their densities be X and masses be Y
So the ratio is 
2x : 5x
And
6y :5y

So we know that 
Density = mass / volume
Hence 
Volume =mass / density
For the first sphere we will have 
Volume = 6y/2x

Volume = 3y/x................... sphere 1
Similarly we will get the volume of second sphere 
Volume =5y/5x

Volume =y/x...................... sphere 2

Hence we have the volume of the sphere.