Question

Ramkali saved Rs. 5 in the first week of a year and then increased her weekly savings by Rs 1.75. If in the \(n^{th}\) week, her weekly savings become Rs 20.75, find n.

Answer 1

Given the values \(a = 5\), \(d = 1.75\), and \(a_n = 20.75\).
We need to find \(n\).
Using the formula \(a_n = a + (n − 1) d\):
\(20.75 = 5 + (n-1)1.75\)
Subtract 5 from both sides: \(15.75 = (n-1)1.75\)
Divide both sides by 1.75: \(n-1 = \frac {15.75}{1.75}\)

\(n-1 = \frac {1575}{175}\)

\(n-1 = \frac {63}{7}\)
\(n − 1 = 9\)
Add 1 to both sides: \(n = 10\)

Therefore, \(n\) is 10.