1. ## solving w/o calculating?

Is there a way to do this problem using logic and avoiding calculations, especially when running out of time? It'd be much appreciated. Thanks.

The 1992 census found that city A had 18% fewer residents than city B. The 1994 census found that city A's population grew by 18% over 1992, while city B's population had remained the same.

Col A: population of city A in 1994

Col B: population of city B in 1994

Ans: B  Reply With Quote

2. hi infinity0,

for this problem u have to calculate but u can make it easy by taking figures which will make your calculation fast n easy  Reply With Quote

3. u dont need to calculate since in 1992 pop. of B is higher A is lower to reach B's pop A's pop. should increase more than %18 this is because if B's pop is 100 A's is 82 18% of 100 is 18 but 18% of 82 is lesser so A's pop in 1994 is not 100 so the answer is B  Reply With Quote

4. yes hace u got a way out for this problem  Reply With Quote

5. I believe you should put the problem down into equations. That should make such problems easier. Youll never get it, if you try to imagine the answer. Otherwise, it was an easy problem.  Reply With Quote

6. If 72.42 = k(24+n/100) where k and n are positive integers and n <100 then k+n

17
16
15
14
13

another problem:

Y X 7 + 6 Y = Y 7 X

In the sum above ,if X and Y each denote one of the digits from 0 to 9 inclusive then X =

9
5
2
3
1
0  Reply With Quote

7. Originally Posted by comp
If 72.42 = k(24+n/100) where k and n are positive integers and n <100 then k+n

17
16
15
14
13

another problem:

Y X 7 + 6 Y = Y 7 X

In the sum above ,if X and Y each denote one of the digits from 0 to 9 inclusive then X =

9
5
2
3
1
0
7242=2400k+kn

k=3
kn=42
n=14
k+n=17

YX7
+6Y
---
Y7X

x=0
y=3

107
+63
---
170  Reply With Quote

8. how u solved this problem ? Please explain.

Another question about ur solution : ur sum shd be 370 instead of 170 as ur taking y =3 ? Originally Posted by hace
7242=2400k+kn

k=3
kn=42
n=14
k+n=17

YX7
+6Y
---
Y7X

x=0
y=3

107
+63
---
170  Reply With Quote

9. Originally Posted by comp
how u solved this problem ? Please explain.

Another question about ur solution : ur sum shd be 370 instead of 170 as ur taking y =3 ?
sorry you r right

first clue is that there is no carry from tens to hundreds

if we look only tens

X
6
-
7

i thought at first X can be 1 if it is 1 then

if we look at unit digits

7
Y
-
1 <<< X

so Y is either -6 or 4 but if it is 4 then there is a carry so the whole calculation is wrong then

I thought let X be zero I didnt tried numbers greater than 1 since if I had used it the same scenario occurs as it occured with X=1

so X=0

by looking tens

X
6
-
7

since X=0 there should be a carry from unit digits

7
Y
-
0 <<<< X

so Y can be -7 or 3 so naturally it is 3 then the sum becomes 10 one carry occurs it adds to tens then th whole calculation is correct  Reply With Quote

10. Thanks a lot , hace Originally Posted by hace
sorry you r right

first clue is that there is no carry from tens to hundreds

if we look only tens

X
6
-
7

i thought at first X can be 1 if it is 1 then

if we look at unit digits

7
Y
-
1 <<< X

so Y is either -6 or 4 but if it is 4 then there is a carry so the whole calculation is wrong then

I thought let X be zero I didnt tried numbers greater than 1 since if I had used it the same scenario occurs as it occured with X=1

so X=0

by looking tens

X
6
-
7

since X=0 there should be a carry from unit digits

7
Y
-
0 <<<< X

so Y can be -7 or 3 so naturally it is 3 then the sum becomes 10 one carry occurs it adds to tens then th whole calculation is correct  Reply With Quote