What is the unit digit of (217)413 × (819)547 × (414)624 × (342)812 ?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 ie 8.
(217)413 × (819)547 × (414)624 × (342)812
For unit digits, the last two digit of power is considered
= (7)13 × (9)47 × (4)24 × (2)12
= (7)1 × (9)1 × (4)2 × (2)4 (cyclicity)
= 7 × 9 × 6 × 6
3 6
= 3 × 6
= 18
8 = unit digit