Atennis supply store pays a wholesaler 90 for a tennis racquet and sells it for 144 what is the markup rate

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. after tax the total is 45.99. what percentage of the subtotal is the total?

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?

Prove that 16^4-2^13-4^5 is divisible by 11.