Question

(3,28) is a factor pair of a certain number. What can be other factor pair?

• A. (7, 18)
• B. (3, 19)
• C. (21, 4)
• D. (4, 17)

Answer 1

The correct option is C (21, 4)

A factor pair for a number contains two factors such that their product is the number itself.
Thus, if (3, 28) is a factor pair of a certain number, then that number is given by the product of the two numbers in the factor pair, i.e., 3 x 28 = 84.
Now to find the other factor pair out of the given options, it must be ensured that the product of the two numbers in the pair equals 84. Let's check for each of the options.
(7, 18): 7 x 18 = 126
(3, 19): 3 x 19 = 57
(21, 4): 21 x 4 = 84
(4, 17): 4 x 17 = 68
Hence, the other factor pair can be (21, 4).