Which pair is equivalent to 2:5?

Which pair is equivalent to 2:5?

• A. 4:10
• B. 3:7
• C. 6:15
• D. 2:4

Answer: (A)

Equivalent ratios carry the same value. You can get them by multiplying both parts of a ratio by the same whole number. Starting with 2 and 5, doubling both gives a new pair that expresses the same relationship, and multiplying by 3 would give yet another equivalent pair. The other given pairs don’t keep that same proportion: one reduces to 1:2, which is not equal to 2:5, and another has a different ratio altogether (not 2:5). A quick check is to cross-multiply: for any pair a:b, if 2×b equals 5×a, they are equivalent.

Equivalent ratios carry the same value. You can get them by multiplying both parts of a ratio by the same whole number. Starting with 2 and 5, doubling both gives a new pair that expresses the same relationship, and multiplying by 3 would give yet another equivalent pair. The other given pairs don’t keep that same proportion: one reduces to 1:2, which is not equal to 2:5, and another has a different ratio altogether (not 2:5). A quick check is to cross-multiply: for any pair a:b, if 2×b equals 5×a, they are equivalent.