What is the length of the platform?
Aptitude Solved Problems
What is the length of the platform?
1. A man purchased a bicycle for Rs. 4800 and sold it immediately at Rs. 5995, allowing the buyer a credit of one and a half years. If the rate of interest is 6%, then find the man gains?
Answer: Rs. 700
Explanation:
Amount = Rs. 4800
Selling price ( Present Worth of Rs. 5995 due 1.5 years ) = ( Amount * 100 ) / ( 100 + ( Rate * Time ))
= ( 5995 * 100 ) / ( 100 + ( 6 * 1.5 ))
= ( 5995 * 100 ) / ( 100 + 9 )
= ( 5995 * 100 ) / 109
= 55 * 100
= 5500
Gain = Selling Price - Cost price
= 5500 - 4800
= Rs. 700
∴ Gain of the man is Rs. 700.
2. Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?
Answer: 6 : 11
Explanation:
Part filled by ( A + B + C ) in 3 minutes = [ 3 * ( 1 / 30 ) + ( 1 / 20 ) + ( 1 / 10 ) ]
= [ 3 * ( 1 / 30 ) * ( 1 / 20 ) * ( 1 / 10 ) ]
= [ 3 * ( 2 + 3 + 6 ) / 60 ]
= [ ( 3 * 11 ) / 60 ]
= 11 / 20
Part filled by C in 3 minutes = 3 / 10
Required ratio = ( 3 / 10 ) * ( 20 / 11 )
= 6 / 11
= 6 : 11
∴ After 3 minutes proportion of solution R is 6 : 11.
3. A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?
Answer: 350 metre
Explanation:
Speed = ( Distance / Time )
= ( 300 / 18 ) m/sec
= ( 50 / 3 ) m/sec
Let the length of the platform be x metres.
Then, ( ( x + 300 ) / 39 ) = ( 50 / 3 )
3 * ( x + 300 ) = 39 * 50
3x + 900 = 1950
3x = 1950 - 900
x = 350 m
∴ Length of the platform is 350 metre.
What is the length of the platform?
1. A man purchased a bicycle for Rs. 4800 and sold it immediately at Rs. 5995, allowing the buyer a credit of one and a half years. If the rate of interest is 6%, then find the man gains?
Answer: Rs. 700
Explanation:
Amount = Rs. 4800
Selling price ( Present Worth of Rs. 5995 due 1.5 years ) = ( Amount * 100 ) / ( 100 + ( Rate * Time ))
= ( 5995 * 100 ) / ( 100 + ( 6 * 1.5 ))
= ( 5995 * 100 ) / ( 100 + 9 )
= ( 5995 * 100 ) / 109
= 55 * 100
= 5500
Gain = Selling Price - Cost price
= 5500 - 4800
= Rs. 700
∴ Gain of the man is Rs. 700.
2. Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?
Answer: 6 : 11
Explanation:
Part filled by ( A + B + C ) in 3 minutes = [ 3 * ( 1 / 30 ) + ( 1 / 20 ) + ( 1 / 10 ) ]
= [ 3 * ( 1 / 30 ) * ( 1 / 20 ) * ( 1 / 10 ) ]
= [ 3 * ( 2 + 3 + 6 ) / 60 ]
= [ ( 3 * 11 ) / 60 ]
= 11 / 20
Part filled by C in 3 minutes = 3 / 10
Required ratio = ( 3 / 10 ) * ( 20 / 11 )
= 6 / 11
= 6 : 11
∴ After 3 minutes proportion of solution R is 6 : 11.
3. A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?
Answer: 350 metre
Explanation:
Speed = ( Distance / Time )
= ( 300 / 18 ) m/sec
= ( 50 / 3 ) m/sec
Let the length of the platform be x metres.
Then, ( ( x + 300 ) / 39 ) = ( 50 / 3 )
3 * ( x + 300 ) = 39 * 50
3x + 900 = 1950
3x = 1950 - 900
x = 350 m
∴ Length of the platform is 350 metre.
Comments
Post a Comment