Triangle a′b′c′ is the image of triangle abc after a dilation. what is the scale factor of the dilation?

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much

Liz had 140 pens and inna had 100 pens. after inna gave liz some pens, liz had 3 times as many pens as inna. how many pens did inna give liz?

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?