Solve this please i will mark him/her the brainlest if they anyone solve it Sam drives from home 40 km at constant speed of 60 km/h to pick his friend and another 80 km with a constant speed of 100km/h to reach the school

How much time did Sam take to reach his friend’s place from his home? *

1 point

1/3 hour

2/3 hour

4/3 hour

1 hour

How much time will he take to reach school after picking up his friend? *

1 point

1/5 hour

2/5 hour

3/5 hour

4/5 hour

How much time did Sam take to travel from home to school? *

1 point

22/5 hour

6/3 hour

6/5 hour

6/8 hour​

Which of the following is an example of a rational number? a. π b. √ 9 c. √ 8 d. 3.8362319

The perimeter of an equilateral triangle is 4 cm more than the perimeter of a square and the length of a side of the triangle is 8 cm more than the length of a side of the aware. find the length of a side of the equilateral triangle

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?