- Shyam,Seenu,Rio,Tippu,and Neetu are five friends .The sums of the weights of each group of four are 130,140,113,131 and 126 .What is the positive difference of the weights of the heaviest and weakest among them?
Let the sum of weight of five friends be W.Let the weight of friends be x,y, z,t,s.
ie) 4S=640 implies S=160.
For heaviest, take S-y=140160-y=140y=20
Weakest ,Take S-z=113160-z=113z=47
Therefore, difference =47-20=27.
- 15 pairs of competitors were participated in a competition . Each one of the pair gave a pack of gifts to everyone except their pair and no exchange of gifts took place between the pairs. How many gifts were exchanged among them?
Total no of competitors = 15 pairs= 30 members .
In 15 pairs ,One of the pair exchange gifts to others except their own pair.
1 member exchange 28 gifts. ie) to 14 pair. (except themselves and their pair)
15 members exchange 15×28=420 gifts.
- Anu deposits certain amount on a bank and got simple interest Rs.280 for two years . And the compound interest of same amount be Rs. 291.2.If the rate of interest is same in two cases , then what is the principal amount Anu deposits?
Rs. 1750.Rs. 2750.Rs. 1050.Rs. 1700Rs. 3750.Option A
Let Simple interest be x for first year and it will be remained in second year also.
Since rate of interest same, Compound interest of first year also x.
But for Second year compound interest =x + a ( a is the inerest of x).
Simple interest for 2 years = 2x = 280 and compound interest = 2x+a = 291.2
280+ a= 291.2
a = 11.2
Since‘a’ is the interest of x,
Rate of interest r = a/x x 100
r = 11.2/140 x 100 r= 8
Rate of interest of 2x is 16 %.
16% of principal P
P= 280/ 16 x 100 = Rs. 1750.
- A train travels at 20 kmph, and reaches its destination at 3.pm.If it travels at 30kmph it reaches at 11.am. At what speed it should be travel to reach at 1.pm.?
Let the time of a train to reach 1pm be t. ie) t= 1.pm
t+2 = 11.am
t+4 = 3.pm
t, t+2,t+4 are in arithmetic progression
if time is in A.P then corresponding speed will be in HP.
20, x, 30 in HP. ( x = speed of a train to reach at 1.pm)
Then Harmonic mean of 20 and 30 x= 2 x 20 x 30/ 20 +30
The speed of the train is 24kmph to reach 1.pm.
- In school hostel rice is stocked for 10 people for 40 days. After 15 days 5 students went for vacation .How many number of days for which the remaining food last?
Let 15 days after 5 people had food be x days.
Less people more food (indirect proportion)
ie) 5:10:: 40:x
5 X x = 10 x 40
x = 80.
Therefore rice remains 80 days for 5 people.
- How many multiples of 2 are there in 10 to 80?
Multiples of 2 =>last digits must be 0, 2, 4, 6, 8
And first digit 1,2 ,3,4,5,6,7,
So there are 7 choices for the first number and 5 choices for the second number.
So there are 5x 7 =3 5 + 1= 36 (include 80) multiples of 2 in between 10 and 80.
- In a shop two partners invested in the ratio 10:20 and they got the profits in the ratio 5:4.If the first partner invest the money for 10 months the how many months the second partner invested?
Investment ratio: 10:20
Profit ratio :5:4
First partner invested 10 months.
Second parner invested x (take) months.
So 10 x 20 / 10 x x = 5/4
20/x = 5/4
x = 16 months
- Two glasses of equal capacity contains sand and color powder.The ratio of the mixing is 2:3 and 5:4 respectively. These mixture are transferred into a big bowl.Then what is the ratio of sand and color powder in the bowl?
9: 49: 35: 29: 27: 7Option E
Ratio= 2 + 5 : 3+4 = 7: 7
- Two triangles having the ratio s of area 5:3. Height ratio 3:2.Find the ratio of the base.
Let the base be x and y of two triangles.
Heights are 3h and 2h.
(½ X x X 3h) /( ½ X y X 2h) = 5/3
x/ y = 5/ 3 x 2/ 3 = 10/6 =>x:y= 10: 6=5:3
- If (64 ^2) – (36^ 2) = 20 x X .Find the value of X?
20 x X = (64 2) – (36 2)
= ( 64 + 36) (64 -36) = 100 x 28 =2800
X= 2800/20 =140