This is really confusing-please help me

SVA Ltd. is preparing Budget for 2009. Data relating to sales, prices and costs are as follows:

Sales Price = Rs. 20.00 per unit
Variable Cost = Rs. 12.00 per unit
Fixed Costs = Rs. 2,00,000 per year

Quantity-probability
15000-10%
20000-10%
25000-10%
30000-20%
35000-30%
40000-10%
45000-10%

What are the probabilities of achieving sales volume of (1) 32500 units and (2) 18750 units.

As per my calculations the answer is (1)50% (2)90%

But, as per book the answer is (1)50% (2)10%

Please show your calculations.