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skawal · 05-20-2008, 04:31 PM

S=1-(1/2)+(1/3)-(1/4)+(1/5)-(1/6)+(1/7)-(1/8)+(1/9)-(1/10)
S=(1/2)+(1/3)-(1/4)+(1/5)-(1/6)+(1/7)-(1/8)+(1/9)-(1/10)
S=(1/2)[1+1/2 +1/3 +1/4 +1/5] +1/3 +1/5 +1/7+1/9

keep special eye to the bold terms.from the term you can see that this term [1+1/2 +1/3 +1/4 +1/5] is greater than 1 and 1/2 of these is greater than 1/2.if we add this number(greater than 1/2) with the another term [1/3 +1/5 +1/7+1/9] then we get a number that is also greater than 1/2.

so the ans is A.

for the first problem
1+2+3+4+5..........+47+48 separate it with the sum of the even integers and the odd integers.then we get

2+4+............+48 and 1+3+................47

no.of terms is = (24-1)+1=24 for both the cases.

sum of the even integers= [2*2 +(24-1)2]*24/2=300=V
sum of the even integers= [2*1 +(24-1)2]*24/2=288=D

so we can see that D+23 is greater than V.

For the last problem
72.42=k(24+ n/100) from the problem if k and n are positive integers and n is less than 100 you can easily make an assumption that k must me a number which is 3 to make balance of the equation that means 3*24 is equal to 72 and 3*(n/100) will give you .42

3*(n/100)=.42
so,n=14

so,k+n=14+3=17.

give me response whether im correct or not.

05-20-2008, 04:31 PM	#2 (permalink)
skawal Within my grasp! Join Date: Jan 2008 Location: bangladesh Posts: 368	S=1-(1/2)+(1/3)-(1/4)+(1/5)-(1/6)+(1/7)-(1/8)+(1/9)-(1/10) S=(1/2)+(1/3)-(1/4)+(1/5)-(1/6)+(1/7)-(1/8)+(1/9)-(1/10) S=(1/2)[1+1/2 +1/3 +1/4 +1/5] +1/3 +1/5 +1/7+1/9 keep special eye to the bold terms.from the term you can see that this term [1+1/2 +1/3 +1/4 +1/5] is greater than 1 and 1/2 of these is greater than 1/2.if we add this number(greater than 1/2) with the another term [1/3 +1/5 +1/7+1/9] then we get a number that is also greater than 1/2. so the ans is A. for the first problem 1+2+3+4+5..........+47+48 separate it with the sum of the even integers and the odd integers.then we get 2+4+............+48 and 1+3+................47 no.of terms is = (24-1)+1=24 for both the cases. sum of the even integers= [22 +(24-1)2]24/2=300=V sum of the even integers= [21 +(24-1)2]24/2=288=D so we can see that D+23 is greater than V. For the last problem 72.42=k(24+ n/100) from the problem if k and n are positive integers and n is less than 100 you can easily make an assumption that k must me a number which is 3 to make balance of the equation that means 324 is equal to 72 and 3(n/100) will give you .42 3*(n/100)=.42 so,n=14 so,k+n=14+3=17. give me response whether im correct or not.