Q. If 5^x – 3^y = 13438 and 5^(x-1) + 3^(y+1) = 9686, then x+y equals?
Answer: 13
Solution:
Given,
5^x – 3^y = 13438—–(1)
5^(x-1) + 3^(y+1) = 9686—-(2)
From equation 2, we get
5^x /5 + 3. 3^y = 9686
Multiplying equation 1 by 3 and adding, we get
5^x = 15625
So, x = 6
Putting x in equation 1, we get
3^y = 2187
Y = 7
So, x+y = 13
a) 1000+ Videos covering entire CAT syllabus b) 2 Live Classes (online) every week for doubt clarification c) Study Material & PDFs for practice and understanding d) 10 Mock Tests in the latest pattern e) Previous Year Questions solved on video