Which of the following sums can be represented as a terminating decimal?

Answer Choices

Correct answer marked below

1/30 + 1/42

1/250 + 1/1,500

1/12,000 + 1/15,000

1/90 + 1/42

1/80 + 1/10

Correct

See the full step-by-step explanation

You can see the correct answer above. Sign in for free to unlock the complete worked solution.

Track your performance and improve

Get detailed analytics, unlock full explanations, and move up difficulty tiers as you practice.

Start for free Sign in

Explanation

Preview

Official Explanation

Official

A fraction is considered to be terminating if, in its simplest form, the denominator contains no prime factors other than 2 and 5.

A. 1/30 + 1/42 --- 1/42 has a prime factor of 7 in the denominator.

B. 1/250 + 1/1,500 --- 1/250 has a prime factor of 5, but 1/1,500 has a prime factor of 3 in the denominator.…

Read the full explanation

Create free account Sign in

Comments

ArjunMay 7, 2024

Amazing

NathanNov 22, 2024

thank you very much!

KaushikAug 14

The trick here is remembering that a fraction terminates only if its reduced denominator has just 2s and 5s. So I just checked each denominator's prime factors one by one.

HannahAug 22

You can usually check each one, but the safest move is to reduce each fraction first, because the sum might reduce further and hide a 3 or 7.

NikhilJun 24

thanks, this was a nice one. spent way too long on D though, kept staring at 42 before realizing 90 also has a 3

What this question tests

What it tests

Your ability to convert between fractions, ratios, and decimals and to reason proportionally.

Common trap

Cross-multiplying incorrectly or mixing up the ratio parts — a part:part ratio is not a fraction of the whole.