TANCET 2014 Quant Q43: Number Theory

This question appeared as Q43 in the quantitative reasoning (aptitude) section of the TANCET 2014. A total of 20 questions appeared in this section in TANCET 2014. This question is a medium level difficulty question and tests the concept in rules of indices in number theory and number properties.

Question

The value of 6ab²c³ * 4b^-2c^-3d is

1. 6a
2. 4b
3. 24ad
4. 4d
5. 0

  Correct Answer      Choice (3). The value of 6ab²c³ * 4b^-2c^-3d is 24ad.

Explanatory Answer

Rules of Indices

a^m * aⁿ = a^{(m + n)}
a^m * a^-n = a^{(m - n)}
a⁰ = 1

Group like terms together
6ab²c³ * 4b^-2c^-3d = (6 * 4)ab²b^-2c³c^-3d = (6 * 4)ab^{(2 - 2)}c^{(3 - 3)}d
= 24ab⁰c⁰d
= 24ad

  The correct answer is Choice (3).

Video Explanation

More XAT TANCET Practice Questions in Number Theory & Number Properties