Question

Find the unit digit of of \( 27^{15^{17^{21}}} \) is A) 3 B) 7 C) 1 D) 9 Find the last digit of \( 225^{66^{33}} \) ? A) 0 B) 3 C) 4 What is the units digit in the product \( \left(3^{65} \times 6^{59} \times 7^{71}\right) \)

          Find the unit digit of of \( 27^{15^{17^{21}}} \) is
A) 3
B) 7
C) 1
D) 9

Find the last digit of \( 225^{66^{33}} \) ?
A) 0
B) 3
C) 4

What is the units digit in the product \( \left(3^{65} \times 6^{59} \times 7^{71}\right) \)

Find the unit digit of of 27^15^17^21 is
A) 3
B) 7
C) 1
D) 9

Find the last digit of 225^66^33 ?
A) 0
B) 3
C) 4

What is the units digit in the product (3^65× 6^59× 7^71)

Added by Belen J.

Comprehensive Mathematics for JEE Advanced

Ravi Prakash; Ajay Kumar; Usha Gupta 2019 Edition

Chapter 6

Instant Answer

Solved by Expert Gaurav Kalra

07/18/2021

Step 1

- The unit digit of 27 is 7. - The powers of 7 cycle every 4: \(7^1 = 7\), \(7^2 = 49\) (unit digit 9), \(7^3 = 343\) (unit digit 3), \(7^4 = 2401\) (unit digit 1), and then it repeats. - We need to find \(15^{17^{21}} \mod 4\). - Any odd power of 15 will be Show more…

Show all steps

Thanks for your feedback!

Find the unit digit of of \( 27^{15^{17^{21}}} \) is A) 3 B) 7 C) 1 D) 9 Find the last digit of \( 225^{66^{33}} \) ? A) 0 B) 3 C) 4 What is the units digit in the product \( \left(3^{65} \times 6^{59} \times 7^{71}\right) \)