The total cost of 18 pens and 23 pencils is Rs. 231, while the total cost of 7 pens and 13 pencils is Rs. 102. What is the cost of 4 pens and 9 pencils?

What is the value of a⁵ × a⁷ ?

The simple interest for four years is one fourth of the principal. At the same rate, which amount become Rs.450 total amount in 2 years?

The heights of Arun’s family members are given in cm’s as 165, 180, 181, 163, 172, 180, 162 The median height of the family will be

A train 150 m. long is running with a speed of 68 km. /hr. In what time will it pass a man who is running at 8 km. /hr. in the same direction in which the train is going?

A and B together can complete a particular task in 4 days. If A alone can complete the same task in 6 days, how many days will B take to complete the task if he works alone? 

Excluding stoppages, the speed of a bus is 80 kmph and including stoppages, it is 60 kmph. For how many minutes does the bus stop per hour?

Find the value of $$ {\sqrt{4+\sqrt{44+\sqrt{10000}}}}$$.