A man earns ₹ 20 on the first day and spends ₹ 15 on the next day. He again earns ₹ 20 on the third day and spends ₹ 15 on the fourth day. If he continues to save like this, how soon will he have ₹ 60 in hand?
(a)On 17th day
(b)On 27th day
(c)On 30th day
(d)On 40th day
Answer
Answer (as printed): A
Explanation
Money earned in 2 days $=₹(20-15)=₹ 5$. Money earned in 16 days $=₹\left(\frac{5}{2} \times 16\right)=₹ 40$. On 17th day, money in hand $=₹(40+20)=₹ 60$.
Explanation as extracted from the printed page; notation may be imperfect.