Pls me on question 4 it is true of false and it is super easy sixth grade stuff

Abaseball picther can throw a ball at about 90 miles per hour, v = 40 m/s, on solid rock ground. we now put him into space. when he throws the ball, which weighs mb = 0.15 kg moves away from himat the same speed. how long does it take the ball thrown in space to travel the 30 meters to the batter? he weighs mp = 100kg

Ineed the answers for these promblems i have

For which pair of objects would adding the same a