Direction: what should come in place at question mark(?).

$$ {4\over 7}×{2{4\over 5}÷{2\over 5}=?}$$

Direction: what should come in place at question mark(?).

(0.85% of 405) +(2.25% of 550)=?

Direction: what should come in place at question mark(?).

$$ {1\over 8}×(223+?)=71$$

Direction: what should come in place at question mark(?).

$$ {\sqrt{4489}+(71)^{2}-(?)^{2}=2707}$$

Direction: what should come in place at question mark(?).

45% of 224×?% of 120=8104.32

Interest earned by Ramesh on Rs.10,000 for 2 years at R% p.a. simple interest is how much more/less than interest earned by him on Rs. 8000 for 2 years at (R+10)% p.a. compounding annually. If Rs. 2000 is invested at 2R% p.a. simple interest for a year, then it would fetch an interest of Rs.400.

If all three pipes are opened for 2 minutes to fill the tank each alternatively in the sequence of A then C and then B.  Calculate water filled by pipes A is what % of water filled by pipe C?

If efficiency of B increased by $$ {33{1\over 3}{\%}}$$ and A and B start work together, while at the same time C starts destroying the work. Find in how many days work will be completed?