## Speed Distance & Time, Compound Interest

**Aptitude Solved Problem****Questions :**

**1. A 600m long train is running at 90 Kmph. how much time it will take to cross an electric pole?**

**2. One card is randomly drawn from a pack of 52 cards. What is the probability that the card drawn is a face card (Jack, Queen or King)**

**3. At what rate of compound interest per annum will a sum of Rs. 1200 become Rs. ****1348.32**** in 2 years?**

**4. A bag contains 50 P, 25 P and 10 P coins in the ratio 5 : 9 : 4, amounting to Rs. 206. Find the number of coins of each type respectively.**

**Answers :**

**1. 20 seconds.**

**2. ( 3 / 13 ).**

**3. 6 %.**

**4. 200, 360, 160.**

**1. Explanation:**

**Distance = Speed * Time****600 = 90 Kmph * Time****600 = [ 90 * ( 5 / 18 ) ] * Time****600 = 30 * Time****= 600 / 30****= 20 Sec**

**∴ It will take 20 seconds to cross an electric pole.**

**2. Explanation:**

**Total number of cards, n ( S ) = 52****Total number of face cards, n ( E ) = 12****P ( E ) = n ( E ) / n ( S )****= ( 12 / 52 )****= ( 3 / 13 )**

**∴ The probability is ( 3 / 13 )**

**3. Explanation:**

**Let the rate be R% per annum.****Then, 1200 * [ ( 1 + R ) / 100 ]2 = ****1348.32****[ 1 + ( R / 100 ) ]2 = ****134832 / 120000****[ 1 + ( R / 100 ) ]2 = ****( 11236 / 10000**** )****[ 1 + ( R / 100 ) ]2 = ****( 106 / 100 )2****1 + ( R / 100 ) = ****106 / 100****( R / 100 ) = ****( 106 / 100**** ) – 1****( R / 100 ) = ****( 106 – 100**** ) / 100****R = ( 6 * 100 ) / 100****R = 6%**

**∴ Rate of interest is 6 %.**

**4. Explanation:**

**Let ratio be x.****Hence number of coins be 5x ,9x , 4x respectively.****Now given total amount = Rs.206****(0.50) (5x) + (0.25) (9x) + (0.10) (4x) = 206****2.5x + 2.25x + 0.4x = 206****5.15x = 206****we get x = 40****Number. of 50p coins = 5x****( 5 * 40 ) = 200****Number. of 25p coins = 9x****( 9 * 40 ) = 360****Number of 10p coins = 4x****( 4 * 40 )= 160**

**∴ The number of coins are 200, 360, 160.**