Question 826513
 It take 15 days for 6 people to complete 10 projects,
Find no. of man-days required to complete the 10 project
15 * 6 =  90 man-days
then
{{{90/10}}} = 9 man-days to do 1 project
:
how many days 9 people will take to complete 14 projects,
Find how many man-days required to do 14 projects
9 * 14 = 126 man-days
Let d = no. of days required by 9 people to do the 14 projects
9d = 126
d - 126/9
d = 14 days for 9 people to complete 14 projects