Sanjeevni · 2026-09-18 · 1 helpful
Its a permutation and combination set. Think of keys as the passcode in your phone and you are allowed to press two numbers wrong but six numbers need to be right...so there are many ways to press the two numbers wrong and other six need to be right. So in this set, according to the questions we need to find the number of combinations we can use to press the keys.