Question 253287
This is a binomial distribution B(12,0.4)
The chance of exactly 7 getting over is 12C7 x (0.4)^7 x (0.6)^5
12C7 = 792  0.4^7 = 128/78125 and 0.6^5 = 243/3125
Multiplying up gives 0.1009023713 so lets call it 10%