Sum of digits of the smallest number by which 1440 be multiplied

Home » Aptitude » Simplification » Question

Sum of digits of the smallest number by which 1440 be multiplied so that it becomes a perfect cube, is

1. 4
2. 6
3. 7
4. 8

Correct Option: B

1440 = 2 × 2 × 2 × 2 × 2 × 3 × 3 × 5 = 2³ × 2² × 3² × 5
To make 1440 a perfect cube, it must be mulitplied by 2 × 3 × 5 × 5 = 150.
∴ The required sum = 1+5 + 0 = 6