The answer is 49.9 because he thought of a number and added 9.5 and the result was 59.4 then you should do 59.4-9.5 and the answer is 49.9
Maria do 1/2 work in 1 hour
Sasha do 1/3 work in 1 hour
Thus,
1/2+1/3=5/6 work in 1 hour
5/6 work in = 1 hour
1 work in =6/5=1.2 hours =72 minutes