Pennies are packaged 50 in a roll. a mother gave her son 161 pennies for his bank and she had 39 pennies left over. how many rolls of pennies did she use? 6 rolls 5 rolls 7 rolls 4 rolls

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.