Number of images formed by two inclined plane mirrors

Explanation

In `Delta ABC`
`angle ABC = 50^@`
` angle ACB = 70^@`
But ` angle ACB + angle ABC + angle CAB = 180^@`
`70 + 50 + angle CAB = 180^@`
` angle CAB = 180 - 120 = 60^@`
`n = (360^@)/(theta) - 1 = (360^@)/(60^@) - 1 = 6 - 1 = 5`