Question
An amount was invested at a simple interest rate. After 6
years, it amounted to (126/108) times the amount it had reached in 4 years. What is the rate of interest per annum?Solution
ATQ,
Let the rate of interest be βr%β p.a.
Let the amount after 4 years = Rs. β108xβ
So, amount after 6 years = (126/108) Γ 108x = Rs. β126xβ
Interest in 2 years = 126x β 108x = Rs. β18xβ
So, yearly interest = 18x / 2 = Rs. β9xβ
Principal = 108x β 9x Γ 4 = Rs. β72xβ
ATQ,
72x Γ (r / 100) Γ 1 = 9x
r = (9x Γ 100) / 72x = 12.5
The rate of interest = r = 12.5%
Find the ratio between the speed of the boat and the speed of the stream.
The speed of the boat while travelling upstream is 24km/hr. The boat ...
A boat takes 3 hours to travel 30 km downstream and 5 hours to travel the same distance upstream. What is the speed of the boat in still water?
A man can swim downstream in 12 minutes covering a distance of 600 meters. He takes 15 minutes to cover the same distance upstream. Find the speed of th...
A boat can travel 7.2 km upstream in 18 min. If the ratio of the speed of the boat in still water to the speed of the stream is 7:1. How much time will ...
A launch moves 50 km upstream and 180 km downstream in a combined time of 11 hours. The still-water speed of the launch is 10 km/h faster than the strea...
To go 75 km downstream, a boat takes 5 hours. For the same 75 km upstream, it takes 10 hours more than that. What is the boatβs still-water speed?
Find the total distance covered by boat in each upstream and downstream in 8 hours if the speed of boat in still water and speed of current is 28 km/h a...
A boat can travel 36 km downstream in 45 min. The ratio of the speed of the boat in still water to the speed of the stream is 5: 1. How much time will t...
The time taken by a boat to travel 'd' kilometers downstream is 8 hours, while the time taken to travel (d - 60) kilometers upstr...
The speed of boat in still water is 48 kmph. If it takes 5 hour to go upstream 40 kms, in what time approximately will it return same distance downstrea...