Answer:
Maria solved 0.5 (half) of a problem in 1 min
Step-by-step explanation:
Set up proportion and cross multiply to solve:
15 problems/30 min = x/1 min
x = 0.5
(x+6)(x-1)
factor using the x-box method
x2 + 7x + x2 + 7x + 9 = 3