I think it would be A but I'm not sure ._.
Assuming independence,
prob=P(late,early)+P(early,late)=(1/10)(2/5)+(2/5)(1/10)
Y
A raiz quadrada de 14 seria 3.74165738677 ou 3.7
Arredondamos para 4 já q 7 é próximo de 10
When you use F.O.I.L. on problems you get an answer that looks like this; ax^2 + bx + c. The middle term is bx. To find this term we solve out by multiplication. so x*x + 5*x + 2*x + 5*2 or x^2 + 7x + 10, so the middle term is 7x.