Which number represents a whole number

Shannon mary and john earn a weekly allowance ahannon earns the amount that is 2/3 of what john earns mary earns an amount that is 1 2/3 of what johns earns 20 dollars a week who eaens the greatest allowance and who earns the least

7x^2-9x+5=0 find the discriminant and number of real solutions

Which expression can be used to find the cost of .75 kilogram of cheese at the price of $6.40 per kilogram?