The sum of twice a number and 5 is 21. What is the number?

Question

asked Jan 17, 2023 228k views

2 Answers

Faisal Khan · Answer 1 · 2023-01-18T16:33:17+0000

Hello.

First, "twice a number" means we multiply 2 times that number.

Let the number be s.

Now, the sum of 2 times s and 5 is 21.

The product of 2 and s can be written like so:

$\sf{2s$

Now, the sum of 2s and 5 is 21:

$\sf{2s+5=21$

Subtract 5 from both sides:

$\sf{2s=21-5$

$\sf{2s=16}$

Now, divide both sides by 2:

$\Large\boxed{\sf{s=8}}$

I hope it helps.

Have a nice day.

$\boxed{imperturbability}$

Robert Rossmann · Answer 2 · 2023-01-22T20:43:06+0000

x = 8

Explanation:

Let the required number be x.

According to the given question,

=> 2x + 5 = 21

=> 2x = 21 - 5

=> 2x = 16

=> x = 16/2

=> x = 8