Question

Which equation is true when r = 7 ?

Answer 1

Answer:

7 = 49 ÷ r

Step-by-step explanation:

To find the equation that is true when r = 7, we need to find a number after the equals sign that is a multiple of 7.

Multiples of 7:  

7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77...

Therefore, the only answer option in which the number after the equals sign is a multiple of 7 is:

7 = 49 ÷ r

To prove this, input r = 7 into each of the equations:

   6 = 30 ÷ r

⇒ 6 = 30 ÷ 7

⇒ 6 ≠ 4.285... ← incorrect!

   7 = 54 ÷ r

⇒ 7 = 54 ÷ 7

⇒ 7 ≠ 7.714... ← incorrect!

   7 = 49 ÷ r

⇒ 7 = 49 ÷ 7

⇒ 7 = 7 ← correct!

   9 = 72 ÷ r

⇒ 9 = 72 ÷ 7

⇒ 9 ≠ 10.285... ← incorrect!