The formula for calculating GPE is
GPE = m x h x g
Where m is mass, h is height raised and g is gravity.
To solve the problem we just have to substitute the values we are given
70,000J = 650 x 10 x y
70,000J = 6500 x y
70,000 / 6500 = y
10.769 = y
So, the block of stone has been raised approximately 10.769 metres.