Question

The sum of three consecutive numbers is 789, what are those consecutive numbers?

(a) 262, 263 and 264

(b) 263, 264 and 265

(c) 264, 265 and 266

(d) 265, 266 and 267

I got this question in an internship interview.

The query is from Solving Linear Equations with Variables on Both the Sides in section Linear Equations in One Variable of Mathematics – Class 8

Answer 1

The correct answer is (a) 262, 263 and 264

To explain I would say: Let the first number be x. Since they are consecutive numbers the next number would be (x + 1) and the third number would be (x + 2). Now as the sum of the numbers is given as 789 we solve the equation by adding the three consecutive variables.

x + (x + 1) + (x + 2) = 789

∴ 3x + 3 = 789

∴ 3x = 789 – 3

∴ 3x = 786

∴ x = 262

Hence the three consecutive numbers are 262, 263 and 264.