Given, 18 pumps----2170 tonnes----10*7 hrs.
So, 16 pumps-------2170 tonnes----10*7*18/16 hrs.
And, 16 pumps-------1736 tonnes----10*7*(18/16)*(1736/2170)hrs. = 63 hrs.
So, no. of days req.= 63/9 = 7 days
Answer:
Minus each number to figure out the common difference which is -4.
54-4= 50
50-4= 46
46-4= 42
42-4= 38
Plug in 0 for x and you get 5. Which is your answer :)