The speed of a  boat in still water is 20 kmph and the rate of current is 4 kmph. The distance travelled by the boat downstream in 30 minute is

Rohit starts a business with Rs.6,500 and after 8 months Shyam joins Rohit as his partner. After 4 years the profit is divided in the ratio of 13 : 12. What is Shyam’s contribution in the capital?

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

Recently which campaign of India has been appreciated by the World Health Organization (WHO)?