Initially (2*33 + 1*24)/(2+1) = 30p a gm
So, cost for 100g = 100*30 = 3000p
Later, (1*33 + 2*24)/(1+2) = 71/3 p a gm.
So, cost for 100g = 100*(71/3) = 2366.67p
He saves 3000 – 2366.67 = 633.33p
Concept of weighted average.
Let ‘x’ be the number of perons in the group and let ‘y’ be
amount per head which they have to pay.
Then xy = 2400.
or y = 2400/x
Since two friends have forget the purse, x-2 persons should
share the total amount(2400).
If they share, they have to make an extra contribution of
Rs 100 to pay up the bill
That is x-2 persons should pay y+100 each
or (x-2)(y+100) = 2400
or y+100 = 2400/(x-2)
or y = 2400/(x-2) – 100
Therefore we have got two equations namely,
y= 2400/x and y = 2400/(x-2) – 100
Comparing these two, we get
2400/x = 2400/(x-2) – 100
Solving this we get
x^2 – 2x -48 = 0
or (x-8) (x+6) = 0
or x = 8 or x = -6
Since ‘x’ denote the number of persons, it should be
positive.
So, x = 8.
LCM of 4,6,8 and 10 are 120
So, the least number of four digits is 120*9=1080 ( <1000 )
if rs 12 and rs 15 per meter then 750*12+750*15
1/2:1/3:1/4 = 6:4:3
Ram = 6/13 * 3250 = 1500,
Shyam = 4/13 * 3250 = 1000,
Mohan = 3/13 * 3250 = 750
3600 sec in 1 hr.. 1000 M in 1 km so to covert m/s to km /hr you multiply the value with (3000/1000) .. so 3000 divided by 1000 will give you 18/5 it’s like constant value.. to convert m/s to km/ hr we can use this 18/5.. hope you understand
The last person covered 120.71 meters.
It is given that the platoon and the last person moved with
uniform speed. Also, they both moved for the identical
amount of time. Hence, the ratio of the distance they
covered – while person moving forward and backword – are
equal.
Let’s assume that when the last person reached the first
person, the platoon moved X meters forward.
Thus, while moving forward the last person moved (50+X)
meters whereas the platoon moved X meters.
Similarly, while moving back the last person moved [50-(50-
X)] X meters whereas the platoon moved (50-X) meters.
Now, as the ratios are equal,
(50+X)/X = X/(50-X)
(50+X)*(50-X) = X*X
Solving, X=35.355 meters
Thus, total distance covered by the last person
= (50+X) + X
= 2*X + 50
= 2*(35.355) + 50
= 120.71 meters
Note that at first glance, one might think that the total
distance covered by the last person is 100 meters, as he
ran the total lenght of the platoon (50 meters) twice.
TRUE, but that’s the relative distance covered by the last
person i.e. assuming that the platoon is stationary.
12
If both agree stating the same fact, either both of them speak truth of both speak false.
∴ Probability
=3/5×4/7+2/5×3/7=12/35+6/35=18/35
After the mixing, 1lt of the mixture has 0.8lt of milk and 0.2lt of water. 1lt of milk costs Rs.12 so 0.8lt of milk costs 0.8 x 12 = 9.6
He sells the mixture at Rs.15,
so profit%=(15-9.6)/9.6 x 100 = 56.25%
45 km/hr
7
36, 54, 18, 27, 9, 18.5, 4.5
C
A. Christian Dior