Question
In a school with 400 students, the average of the age of
the boys is 16 years and that of the girls is 12 years. If the average age of the school is 14 years 9 months. Then the number of girls in the school is.Solution
Let the average age of Boys be ‘x’ According to question, x × 16 + (400 - x) × 12 = 400 × 14(3/4) 16x + 4800 - 12x = 400 × 59/4 4x + 4800 = 5900 4x = 1100 x = 275 Number of girls = 400 - 275 = 125 Alternate Method: By Alligation, Boys            Girls 16              12        59/4 59/4 - 12     :   16 - (59/4) 11/4         :      5/4 11          :      5 So Number of girls = 5/(5+11) of 400 = 5/16 of 400 = 125 Â
‘X’ and ‘Z’ began a business with investments of Rs. 5,500 and Rs. 11,000 respectively. After 5 months, ‘Y’ entered the business contributin...
A and B invested Rs.6000 and Rs.9000 in a business respectively and after 5 months B withdrawn 50% of his initial investment and again after 5 months he...
"M" initiated a business with an investment of Rs. 21,000. Subsequently, after a certain number of months, "N" entered the partnership by contributing R...
Nina, Omar, and Paula invest in the business in the ratios of 9:5:p, respectively, and their time periods are 2 months, 3 months, and 4 months, respecti...
A and B enter into partnership. A invests some money at beginning, B invests thrice the amount after 4 months and C invests double the amount after 9 mo...
D, E and F started a company with capital investments in the ratio 5:3:2. F being the active partner gets 10% of the total profit for managing the busin...
A starts business with Rs.8000 and after 6 months, B joins with A as his partner. After a year, the profit divided in the 4:5. What is B’s contributi...
Pooja and Meena are partners in a business. Pooja (working) puts in Rs. 6000 and Meena (sleeping) puts in Rs. 4000. Pooja receives 20% of the profit for...
A and B enter into partnership. A invests some money at beginning, B invests thrice the amount after 7 months and C invests double the amount after 3 mo...
Meera and Tara started a boutique by investing Rs. 3250 and Rs. 2750, respectively. If the annual profit is Rs. 9600, find the difference between their ...
Relevant for Exams:
