Q. The average of 7 subjects of Mr Raj is 75. If 1 subject is decreased, his average decreased/ increased by 3. What is the average of 6 subjects?
TLT:
In case of Decrease= 75 + 6 X 3 =75+18=93
In case of Increase= 75 – 6 X 3 =75-18=57
Q. A student secures 23% marks in an examination but fails by 36 marks. Another student secures 35% marks which are 48 marks more than the required to pass. What is the percentage of marks and marks required to pass?
TLT: Let, Total Marks= 100%
35% – 23% = (48+36)
i.e. 12% = 84
So, 100%= 84/12 X 100
= 700 Total
Pass Marks= 700 X 23/100 + 36
= 161+36 =197
Q. A shopkeeper allows a discount of 25% and 15% on the written price and another shopkeeper allows a discount of 30% and 10% on the written price. Which discount is profitable for the customer?
TLT: Let, Full price= 100%
I> 25% and 15%= 25+15-25 X 15/ 100
= 40-3.75= 36.25%
II> 30% and 10%= 30+10-30X10/ 100
=40-3= 37%
II Discount is more profitable.
Q. A and B are two stations 500 km apart. A train starts from A and moves towards B at 20 km/hr. Another train starts from B at the same time towards A at 30 km/hr. How for from A will they cross each other?
TLT: Speed is prop to distance
Speed Ratio=20:30=2:3
So, Distance Ratio=2:3
:(2+3)=500, i.e. :1=100
A’s distance(:2)=2X100=200
B’s distance(:3)=3X100=300
So, trains will meet 200km from A
Q. A started a business by investing Rs. 1200, after 3 and 6 months B and C joins the business with unequal capital if the end of the year the profit was distributed in the ratio 2:3:5. What is the share of B?
TLT: Profit Ratio ABC=2:3:5
Time Ratio ABC=12:9:6=4:3:2
Capital Ratio=2/4:3/3:5/2
=1/2:1:5/2=1:2:5
A(:1)=1200
B(:2)=2400
C(:5)=6000