Question

name the prime number between 40 and 70 where the ones digit is 5 less than the tens digit. enter the correct answer in the box.

Explanation:

Step1: List 2-digit nums 40-70

Tens digit: 4,5,6

Step2: Calc ones digit per rule

For tens=4: $4-5=-1$ (invalid)
For tens=5: $5-5=0$ → num=50
For tens=6: $6-5=1$ → num=61

Step3: Check primality of valid nums

50 is divisible by 2,5 → not prime
61 has no divisors other than 1 and itself → prime

Answer:

61