M4maths Previous Puzzles

13 Jan 2010 saving plan

What will be the difference of the amounts in the two types of saving given below
1) 10 rupee per day upto 100 days
2) 25 paisa then 50 paisa then 75 paisa then so on upto 100 days

OPtion

(1) 300.00
(2) 250.00
(3) 262.50
(4) 152.50
(5) 98.50
(6) 67.00
(7) 275.00
(8) 122.00
(9) 230.00
(10) 200.50

Solution

In first saving total amount = 1000 rupee
In second, savings of 50th and 51st days are 12.50 and 12.75 rupee
(These two are middle terms)
Total saving in second case = 100*{(12.50 + 12.75)/2} = 1262.50 rupee
Difference is 262.50 rupee

Correct Option: 3 Best Solution (5)

C.T.Narayanan   15 years AGO

First Plan : 10 * 100 = 1000

Second Plan : .25 + .5 + .75 + ... = .25(1+2+...100) = .25 * 100 * 101 / 2 = 1262.5

Difference = 262.5

Like? Yes (2) | No   

saurav   15 years AGO

from the first type of savings Rs(10*100)=Rs 1000 is saved..
where as the second type of savings is an A.P. with a(first term)=25p,d=25p and n=100
applying the formula
S=n*(2*a+(n-1)*d)/2
we get S=Rs 1262.50
therefore the difference of the savings is Rs(1262.50-1000)=Rs 262.50

Like? Yes (2) | No   

Mehul MKDP   15 years AGO

(10*100) = 1000
0.25 0.5 0.75 ... 100 TIMES = 1262.5

Like? Yes (1) | No   

susmit   15 years AGO

first option is 100*10=1000. second option is an a.p. with a=25paisa and d=25 paisa when n is 100

Like? Yes (1) | No   

Siddharth   15 years AGO

per day 10 rupees 4 100 dayz =1000rupees
den 25+50+75.......for 100 dayz paise
=25(1+2+3.....+100) paise
=126250 paise
=1262.50 rupees
the difference is 1262.50-1000=262.50rupees

Like? Yes (1) | No