Answer:
C = 3 3/4 hours
Step-by-step explanation:
To determine the amount of time it takes to do a job we use the formula
1/A + 1/B = 1/C
Where A is the time it takes for person A alone
B is the time for person B alone
and C is the time for A and B togther
1/6 + 1/10 = 1/C
Since 30C is the common denominator, multiply by 30C to clear the fractions
30C (1/6 + 1/10) = 1/C* 30C
5C + 3C = 30
8C = 30
Divide by 8
8C/8 = 30/8
C = 30/8
C = 15/4
C = 3 3/4 hours