Jeremy's house is 45 feet wide. In a photograph, the width of the house was 2.5 inches and its height was 2 inches. What is the actual height of Jeremy's house?

How do i do this? i don’t understand

In priyas math class there are 10 boys and 15 girls. what is the ratio of boys to girls in priyas math class? express your answer as a decimal

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?