Cqn you answer this one ps

In cents, what is the least total amount that cannot be obtained by using a combination of fewer than eight coins from a collection of pennies, nickels, dimes and quarters?

Mrs. robinson bought a novel at a bookstore on sale for 20% off its regular price of $29.99. mr chang bought the same novel at a different bookstore for 10% off its regular price of $25. which person received the better discount?

By what fraction name for 1 must 2/3 be multiplied to form a fraction with a denominator of 15