Aptitude - Problems on Numbers - Discussion
Discussion Forum : Problems on Numbers - General Questions (Q.No. 13)
13.
A number consists of 3 digits whose sum is 10. The middle digit is equal to the sum of the other two and the number will be increased by 99 if its digits are reversed. The number is:
Answer: Option
Explanation:
Let the middle digit be x.
Then, 2x = 10 or x = 5. So, the number is either 253 or 352.
Since the number increases on reversing the digits, so the hundred's digits is smaller than the unit's digit.
Hence, required number = 253.
Discussion:
22 comments Page 3 of 3.
Laxmikanta said:
1 decade ago
Lets Suppose three digits are a,b,c
Than a+b+c=10
But b=a+c (given)
a+c+b=10
(a+c)+b=10
b+b=10
b=10/2=5
so the middle digit is 5
so a=3or2 and c=3or2 (3+2=5)
thats why the number is either 253 or 352
But the actual no is 99 less than the reverse no.
352-253=99
: . so the no is 253
Than a+b+c=10
But b=a+c (given)
a+c+b=10
(a+c)+b=10
b+b=10
b=10/2=5
so the middle digit is 5
so a=3or2 and c=3or2 (3+2=5)
thats why the number is either 253 or 352
But the actual no is 99 less than the reverse no.
352-253=99
: . so the no is 253
(1)
Ramya said:
2 decades ago
I dont understand concept .....pls post ur answers
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