sandy gets 3 marks for each correct sum and loses 2 marks for each incorrect sum . sandy attempts 30 sums and obtains 50 marks . how many sums did sandy get correct ?
n0 = 3.0
n1 = 2.0
n2 = 30.0
n3 = 50.0
t0 = n0 + n1
t1 = n1 * n2
t2 = n3 + t1
answer = t2 / t0
print(answer)