The average age of a family of 18 members is 82 years. If the age of the youngest member is 12 years, the average age of the family at the birth of the youngest member was?
Total age of the family of 18 members = 82* 18 = 1476 yrs
Total age of the family members 12 yrs ago = 1476 - (18*12) = 1260
At the time total members in a family = 18
Average age of the family at the birth of the youngest member = 1260/18 = 70yrs.
There are four different letters and four different letter boxes, in how many methods these letters can be dropped in the boxes,
if all the four letters in a single box are not allowed:
Total no. of methods without any condition = 4*4*4*4 = 256
No of methods of taking all the four letters in a box = 4
Hence required methods with given condition = 256-4 = 252
Murugan sold a book at a loss of 40%. If the selling price had been increased by Rs.200, there would have been a gain of 10%. What was the cost price of the book?
Let cost price be Rs ‘x’ Then (110% of x) – (60 % of x) = 200 (110x/100) - (60x/10) = 200 110x – 60x = 20000 X = 400 So cost price of the book = Rs.400
Kiran rides her scooter 14km at an average speed of 16 km/hr and again travels 16km at an average speed of 14 km/hr. What is her average speed for the entire trip approximately?
Total distance travelled =14+16=30Km
Time taken to travel 14 km at an average speed of 16 km/hr =14/16=7/8 Hr
Time taken to travel 16 km at an average speed of 14 km/hr =16/14=8/7 hr
Total time taken =7/8+8/7 Average speed =Total distance travelled /Total time taken =30/(7/8+8/7) =30/(113/56)
=30*56/113=1680/113
=14.86 km/hr
A mathematician is a machine for turning coffee into theorems
ALFRED RENYI
As a toddler when I looked at my fingers and wondered,
you helped me to count numbers.
As a kid when I looked at stars with awe,
you helped me and told that's infinity.
As a teen when my confused mind often went blank,
you told that's zero and eventually