1) It is given that a=30 and b=50. If a and b are decrease by 5% and 8% resepectively, find the percentage decrease in their sum.
2) There are two containers of peanut oil, the normal size and the jumbo size. The volume of the normal size is less than of the jumo size by 40% and the difference in volume is 600mL.
(a) Find the volume of the normal size.
(b) If the volume of the normal size is increased by 5%, find its new volume.