Answer:
She need to stuff 1224 envelopes in 6 hours.
Explanation:
Total time for completing = 8 hours
Total number of envelopes = 1500
The first hour, Rachel stuffs 135 envelopes. The second hour she stuffs 141 envelopes.
Total number of envelopes stuffed in 2 hours = 135 + 141 = 276
Remaining number of envelopes = 1500 - 276 = 1224
Remaining time = 8 - 2 = 6 hours
So she need to stuff 1224 envelopes in 6 hours.