Number, decimal fraction and power Quiz 1

D. 1120
Non-faulty & Non-defective=1200- %(faulty+defective)
=1200-[(7/(3*100)) + (13/(3*100))]
=1200-1200*(20/300)
=1120

41x=14x+135
i.e. x=5

The amount is 4 greater than the lcm of 20 25 16 and 18
so the LCM is 3600.
so the amount is 3604

20^2=400
30^2=900
So the number is b/w these -- 25^2=625
26^2=676 + 6=682 so ans=6

f = 0.555... ; (1)
10f = 5.555... ; (2)
9f = 5 ..... (2) - (1)
f = 5/9 ...

As, 2880 = 2^6 X 3^2 X 5
In order to make it a perfect square, all the powers of prime factors should be even.
So, in 2880 powers of prime factors 2 and 3 are even while the power of prime factor 5 is 1 i.e odd.
To make it a perfect sq, we have to multiply 5

Let cost of CD is C
Cost of pen drive is P
3C+2P=790 ----------------(1)
2C+3P=1110 ----------------(2)
Adding these equations, we get
5C+5P=1900
SO, C+P=380
C=380-P -------------------(3)
subtracting the equations 1 & 2
P-C=320
Put Eqn (3) in this
P+P-380=320
So, P=350 Rs.

0.5x-40=250
so x=580
now 1/10th of 580 is 58

0.0282

=>(282/10000)

=> 282/(100^2)

so we can see that the denominator is a perfect square already, so we will have to make the numerator a perfect square to make the whole number a perfect square

now some trial & error

15^2 = 225

16^2 = 256

17^2 = 289

so the least no. which will be added to 282 is 289 - 282 = 7

so 289/10000 = (17/100)^2 is a perfect square

=> 282/10000 + 7/10000 is a perfect square

so we are adding 7/10000 = .0007

512/4=128 Songs
but she has downloaded 3 songs, so 128-3=125
so, 125 songs she initially have in her phone