I don’t know how to do this can someone help?

1foot = 12 inches; 1 yard = 3 feet

On average, how many more hits will he get when he bats 100 times at home during the day as opposed to 100 times away at night?

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is