The answer is 90%. You get this answer by multiplying both the numerator and denominator by 5 so 18x5=90 and 20x5=100 giving you a fraction of 90/100 and a percentage of 90%.
A). Simply, subtract 100 percent minus 65 percent, which gives you the answer 35 percent.
b). So, to find the total number you add 280 plus 65 percent, which gives you the answer, 462.
c). To find this, simply subtract 462 minus 280, which gives you the answer, 182.
Hope this helps!
♤MidnightQueen