Number of successive deductions of 20 %, required to get an object of 100 rupee in 40 rupee 96 pai

M4maths Previous Puzzles

09 Mar 2010 Number of deductions?

Number of successive deductions of 20 %, required to get an object of 100 rupee in 40 rupee 96 paise.

OPtion

1) 8
2) 5
3) 6
4) 7
5) 4
6) 9
7) 1
8) 2
9) 3
10) 10

Solution

Every 20 % deduction reduces the cost to 0.8 multiple of its initial cost.
Thus 100 * 0.8 * 0.8 * 0.8 * 0.8 = 40.96
1st 2nd 3rd 4th
4 deductions are required.

Correct Option: 5 Best Solution (14)

HARMEET KAUR   14 years AGO

40.96x100/80= 51.2
51.2x100/80= 64
64x100/80=80
80x100/80=100
=4times
hence answer is option 5

Like? Yes (1) | No   

S. Singh   14 years AGO

After 1st discount ... value = 100*0.8= Rs. 80
After 2nd discount ... value = 64
After 3rd discount ... value = 51.20
After 1st discount ... value = Rs. 40.96

so 4 deductions

Like? Yes (1) | No   

Saranjit Singh   14 years AGO

After succesive discounts, discounted value will be 80,64,51.2 , 40.96.

so 4 deductions are required.

Like? Yes (1) | No   

Dr.Dipin Singh   14 years AGO

100*(0.8)^4= 40.96

hence ans is 4...option 5

Like? Yes (1) | No   

Dr. Divya   14 years AGO

40.96=100*0.8*0.8*0.8*0.8= 100*(0.8)^4

so 4 times successive deductions of 20 %, required to get an object of 100 rupee in 40 rupee 96 paise.

Like? Yes (1) | No   

Mehul MKDP   14 years AGO

100 -80 - 64 - 51.20 - 40.96

Like? Yes (1) | No   

Pargat Pal Singh   14 years AGO

100*(0.8)^n= 40.96 or (0.8)^n= 0.4096 = (0.8)^4

hence n=4... option 5

Like? Yes (1) | No   

Achelal Sharma   14 years AGO

successively deducting 20% 4 times the value comes to 40.96

Like? Yes (1) | No   

Neha Bhatia   14 years AGO

after 1st time deduction,it will get 80,2nd will approx 65,3rd will approx 50 and 4th will approx 40

Like? Yes (1) | No   

nitin sakhala   14 years AGO

by doing successive deduction you may get 48.96 after 4 successive deduction of 100 rupees moreover the original value become 4/5 of pre-value after deduction

Like? Yes (1) | No   

Vasu   14 years AGO

Before 1st deduction , cost =40.96x100/80= 51.2
Before 2nd deduction, 51.2x100/80= 64
Before 3rd deduction ,64x100/80=80
Before 4th deduction, 80x100/80=100

so 4 deductions are required.

Like? Yes (1) | No   

sivakumar   14 years AGO

100*0.8=80
80*0.8=64
64*0.8=51.2
51.2*0.8=40.96
four successive deductions

Like? Yes (1) | No   

Meena   14 years AGO

100*(1-0.2)^4= 40.96

so 4 times.

Like? Yes (1) | No   

Aashu   14 years AGO

origanal price is 100, every 20% dedeuction reduces the price to 80% it means .8 multiple of its value. Now 100*.8=80, 80*.8=64, 64*.8=51.2, 51.2*.8=40.96, hence 4 deduction are required.....

Like? Yes (1) | No