How can i answer question 19? me, i need the answer now

The spring starts out 22 cm long with nothing hanging on it.

Hanging 35 newtons of weight on it stretches the spring 1 meter.

Ellen is going to hang 250 grams of mass on the spring.
What's the weight of 250 grams of mass ?

   Weight = (mass) x (acceleration of gravity in the place where the mass is) .

On Earth, the acceleration of gravity is 9.8 m/s² .
250 grams is 0.25 of a kilogram.

Weight of 250 grams  =  (0.25 kilogram) x (9.8 m/s²)

                                 =    (0.25 x 9.8)  kg-m/s²

                                 =        2.45 newtons .

2.45 newtons of weight is  (2.45 / 35) of 35 newtons,
so it'll stretch the spring  (2.45 / 35) of a meter.

   2.45/35 = 0.07 of a meter  =  7 centimeters.

The spring was 22 cm long with nothing hanging on it,
and the 250-gm weight stretched it 7 cm.
So with the weight hanging on it, it's (22 + 7) = 29 cm long.

Iknow the first part it is the average star i am not 100% sure