First you would start getting the denominators to the same number and you could do this by multiplying 9/10 by 4, and 7/8 by 5 to get the denominators to 40 and when you add the fractions you get 71/40 so the answer would be D. About 2
In terms of diameter (d), the area (A) of a circle is given by the formula
A = (π/4)d²
You have d=20 yd, so the area of the circle is
A = (π/4)×(20 yd)² . . . . substitute the given information into the formula
A = 100π yd² . . . . . . . . do the arithmetic
A ≈ 314.16 yd²
C 12.5 hours it would take this long because it adds 3 more people and then you like do something and you subtract that Number by 20 and get 12.5 hours