Math BUT USING REVERSE ANSWERING TECH:
Prices have risen 20%. What has happened to the value of the dollar:
Ans. It has gone down 16-2/3%; (not down 25% and not down 20%)
REASON:
STEP1: 100 dollar and 120 dollar [assume you know 20% mean 20 dollar more] and so either 100 / 120 or 120/100 and if you try both, then you know it is 0.833 or 1.2;
STEP 2: 1-0.833 LOOKS the best possible answer because
1-1.2 doesn't make sense at all [price rise 20% and no way will dollar down exactly the same %, right ? and this common sense is based on mathematical experience!!]
Prices have risen 20%. What has happened to the value of the dollar:
Ans. It has gone down 16-2/3%; (not down 25% and not down 20%)
REASON:
STEP1: 100 dollar and 120 dollar [assume you know 20% mean 20 dollar more] and so either 100 / 120 or 120/100 and if you try both, then you know it is 0.833 or 1.2;
STEP 2: 1-0.833 LOOKS the best possible answer because
1-1.2 doesn't make sense at all [price rise 20% and no way will dollar down exactly the same %, right ? and this common sense is based on mathematical experience!!]
