# Part 1/20 of the most important 100 math tricks

Part 1/20 of the most important 100 math tricks. Click here to know the initiative.

Q1. A car travels from P to Q at a constant speed. If its speed were increased by 10 km/h, it would have been taken one hour lesser to cover the distance. It would have taken further 45 minutes lesser if the speed was further increased by 10 km/h. The distance between the two cities is:

(a)540 km

(b)420 km

(c) 600 km

(d) 620 km

Q2. A person sells a table at a profit of 10%. If he had bought the table at 5% less cost and sold for Rs 80 more, he would have gained 20%. The cost price of the table is

(a)Rs 3200

(b)Rs 2500

(c) Rs 2000

(d) Rs 200

Q3. The percentage of loss when an article is sold at Rs 50 is the same as that of the profit when it is sold at Rs 70. The above mentioned percentage of profit or loss on the article is

(a)10%

(b)50/3%

(c) 20%

(d) 68/3%

Q4. A sum becomes Rs 4500 after two years and Rs 6750 after four years at compound interest. The sum is

(a) 4000

(b) Rs 2500

(c) Rs 3000

(d) Rs 3050

Q5.

is equal to

(a) 3

(b) 4

(c) 6

(d) 2

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most important 100 math tricks series : Solution   For video solution click here

1. (b) Solution: from options see which term or number can make factors which has difference one i.e. 6*7: 42 which infers only 420 which  is your answer. It means with speed of 60 km/h it takes 7 hours and speed of 70 it takes 6 hours. No need further processing. In 3 seconds you can solve if you can understand this trick.

2.(c)

If difference is 4 then cp =100

If difference is 80 then cp = (100/4)×80=2000

3. Solution: (b)  Trick used (50+70)/2=60 is CP hence either loss Rs10 or Profit Rs 100

% profit or loss = (10/60)×100=50/3%

4. (c )If amount is Rs 6750 then principal is = Rs 4500

—-do—       Rs 1 —————-= 4500/6750

—-do—       Rs 4500 —————-= (4500/6750)*4500 =3000

5.   (b) Factors of 12  = 4 * 3 , Bigger factor 4. So answer 4.

Note in such type of questions we can make factors which has difference of 1 i.e. in this 4 , 3. If sign is positive we take bigger factor like in this case. If sign was negative i.e. 12- , then we would have taken 3.

Or you can also use other trick like put value from option which will it perfect square. In this case 12+4 is perfect square. So start from last.

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