The value of x in the given equation
$$ {23 ^2 + \sqrt{x}=625}$$

The heights of six people are given as 6 feet 6 inches, 6 feet, 5 feet 8 inches, 6 feet 2 inches, 6 feet 4 inches, and 5 feet 10 inches, respectively. Find the average height of these six people.

A cycle seller gives 10% discount on marked retail price and still earns 26% profit. If marked retail price of the cycle is Rs. 840/- Then how much money was paid by the seller for that cycle?

In what time will the simple interest be $$ {2\over5} $$ of the principal at 8% per annum? 

$${I.{(13)^{2}}-14+28=x}$$
$${II.{(16)^{2}}-8×7=y}$$

Bobby and Billy can complete a job in 28 days and 20 days, respectively. They work together for 5 days, after which Billy leaves the job. In how many days did Bobby alone complete the rest of the job?

If tanx = cot(50+3x), then what is the value of x ?

Triangle PQR is such that PQ=9 cm, QR=6 cm, PR=7.5 cm and triangle PQR is similar to triangle XYZ. If XY=18 cm, find the value of YZ.