Question

1) Bob can type 2 letters in 4 hours while Bill can do it in 6 hours. How many hours would it take them to type six letters together?

AND
2) My brother is 5 years older than me. My sister is 3 years younger than me. How old will my sister be when my brother is 29?
PLS HELP ME WITH BOTH

Answer 1

1) I think it's 15 hours
2) 21