Question

Find the cube root of -2.744.

• A. 1.4
• B. -1.4
• C. 14
• D. -14

Answer 1

The correct option is B -1.4

- 2.744 = $\frac{-2744}{1000}$

By estimation 2744 = 2(group 1) 744(group 2)

The second group has 4 as its unit digit so its root will also have 4 in its unit digit.

Now 2 lies between 1 and 8

The cube root will be between 1 and 2

1 being the smaller of these

So, the tens place of the cube root will be 1

Therefore, the cube root will be 14

Cube root of 1000 = 10

So finally $\frac{-14}{10}$= -1.4