Let the original money with Sandeep be Rs x
So, the money with Gayatri = Rs (x − 50)
After getting Rs 15 each, ratio of their money becomes 3 : 1.
⇒ x + 15 = 3(x − 35)
⇒ x + 15 = 3x − 105
⇒ 2x = 120
⇒ x = 60
∴ The money with Sandeep = x = Rs 60
and the money with Gayatri = x − 50 = 60-50 = Rs 10