If a - b= 3 and a2 + b2 = 29, find the value of ab.
10
12
15
18
Explanation:
2ab = ($ a $2 + $ b $2) - $\left( a - b \right)$2
= $\left(29 - 9\right)$ = 20
$\Rightarrow$ ab= 10.
Next Question
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is: