Daniel is going to buy a pizza. He can choose one pizza variety, one extra topping and one pizza size.

He can choose from

23 different pizza varieties

18 different extra toppings

The total number of ways Daniel can choose the pizza variety, the one extra topping and the

pizza size is 3726

Work out the number of different pizza sizes that Daniel can choose from.

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?