How many minutes is 40% of 120 minutes?

Each month, a shopkeeper spends 5x + 14 dollars on rent and electricity. if he spends 3x−5 dollars on rent, how much does he spend on electricity? for which value(s) of x is the amount the shopkeeper spends on electricity less than $100? explain how you found the value(s).

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class

How can you tell when x and y are not directly proportional?