Question 2551
Let the number of watches be x
The number of beepers be y

As number of watches required is 3 times as much as number of beepers, therefore

x = 3y.....Equation(1)

Cost of 1 watch = $27.98
So cost of x watches will be = 27.98x

Cost of 1 beper = $23.46
So cost of y beepers = 23.46y

Total cost = $537
=> 27.98x + 23.46y = 537

Substituting value of x from equation (1)

=> 27.98*3y + 23.46y = 537
=> 107.4y = 537
=> y = 537/107.4
=> y = 5

So number of beepers = 5
number of watches = x = 3y = 15