The differences between two numbers is 18. If four times the second numbers is less than three times the first number by 18, then what is the sum of these two numbers?

Let first number = p
and second number = q
According to the question,
p - q = 18 ................................(i)
and 3p - 4q = 18.....................(ii)
On multiplying Eq .(i) by 3 and subtracting Eq. (ii) from it,we get
3p - 3q = 54
3p - 4q = 18
q = 36
On putting the value of q in Eq, (i) we get
p = 18 + q
⇒ p = 18 + 36 = 54
∴ Required sum = p + q = 54 + 36 = 90