Oh, dude, it's like finding out how much your favorite snack has shrunk in size. To calculate the percent of change, you subtract the starting number from the final number, divide that by the starting number, and then multiply by 100. So, for this problem, it would be (85 - 136) / 136 * 100. Just plug and chug, my friend.
136
The number 160
-37.5%
Original Price x .85 = 136 Original price = 136/.85 (If you are allowed to use a calculator, you are done here.) IF not, factor and cancel... 136X100/85 = 2x2x2x17x2x2x5x5/17x5 = 2x2x2x2x2x5 = 32 x 5 = 160 160
70%
0.85
85% decrease.
when does this go in effect
17/20
Well, first you need to find out what the 100% number is. To do that you divide 85 by 5 (the lowest common denominator between 85% & 100%) and you get 17. Now you divide 136 by 17 and you get 8. Then, to get the 100% number, you multiply the 8 by 20 (because 20 times 5 (the lowest common denominator) is 100%) and you get 160, your answer. As a double check, calculate 15% of 160 and you get 24, the difference between 136 (85%) and 160 (100%).
136%