Answer:
20
Step-by-step explanation:
If the three numbers are x, x+1, and x+2, then:
x (x+1) (x+2) = 990
x (x² + 3x + 2) = 990
x³ + 3x² + 2x - 990 = 0
(x - 9) (x² + 12x + 110) = 0
Since x must be a whole number, x = 9. You can also use simple trial and error to find that the three numbers are 9, 10, 11.
The sum is:
9 + 10 + 11 = 20
