CAT 2019 Slot 2 — QA Question 26
2 Variable EquationsEasy
In a six-digit number, the sixth, that is, the rightmost, digit is the sum of the first three digits, the fifth digit is the sum of first two digits, the third digit is equal to the first digit, the second digit is twice the first digit and the fourth digit is the sum of fifth and sixth digits. Then, the largest possible value of the fourth digit is
Answer & solution
Answer: 7
Solution
Let the first digit be = a
Second digit = Twice of first digit = 2a
Third digit = First digit = a
Fifth digit = Sum of first two digits = a + 2a = 3a
Sixth digit = Sum of first three digits = a + 2a + a = 4a
Fourth digit = Sum of fifth and sixth digit = 3a + 4a = 7a
Largest possible value of fourth digit = 7 (it has to be a single digit integer)
Hence, 7.