RRB RPF RPSF SI and CONS Model Papers 6 with solutions

(1) The unit’s place digit of 129‌121+ 7867 = Unit’s place digit of 129‌121 + Unit’s place digit of 78‌67 = Unit’s place digit of 9‌121 + Unit’s place digit of 8‌67
= Unit’s place digit of 9‌1 + Unit’s place digit of 8‌3 (since the order of cycles of 9 and 8 are 2 and 4, respectively)
∴Unit’s place digit of (9 + 2) = 1