Sophie opened a picture of a tree on her cell phone screen and zoomed in 2.5 times. The new scale of the picture became 1:168. What would be the scale if it was zoomed in 4 times ?

Last year the original prices of Emma's and Sophie's phones were $560 and $640. Now the prices reduced in ratios 7:6 and 4:3 respectively. What is the difference of the current prices ?

If 5 men or 7 women can earn $315 in a day, find how much 7 men and 11 women can earn in three days ?

Jack wanted to measure the weight of his luggage at the airport before departure. He was surprised to see that it weighed 23.6 kg. Then he stood on the weight with and without his luggage and understood that the scale is malfunctioning as the last two weights of 91.2 kg and 65.5 kg were obviously off. What was the true weight of his luggage?

PLEASE HELP