What is 7.849+0.09? can you help me find the answer?

Given that half of the personal music players sold by a particular brand have a flaw. If the player has the flaw, it dies in the first six months. If it does not have this flaw, then only 20% fail in the first six months.
Let A be the event that it fails in I 6 months
B1 = it has a flaw
B2 = it does not have a flaw
B1 and B2 are mutually exclusive and exhaustive
the chances that it has this flaw
=The probability that it has the flaw is

7 0

3 years ago

2067 Supp Q.No. 2a Find the sum of all the natural numbers between 1 and 100 which are divisible by 5. Ans: 1050

Alborosie

5

Answer:

1050

Step-by-step explanation:

Natural Numbers are positive whole numbers. They aren't negative, decimals, fractions. We can just divide 5 into 100 to find how many natural numbers go up to 100 and just add them but that is just to much.

There is a easier method.

E.g: Natural Numbers that are divisible by a Nth Number. is the same as adding the Nth Numbers to a multiple of that Nth Term. For example, let say we need to find numbers divisible by 2. We know that 4 is divisible by 2 because 4/2=2. We can add the Nth numbers which is 2 to 4. 4+2=6. And 6 is divisible by 2 because 6/2=3. We can call this a arithmetic series. A series which has a pattern of adding a common difference

Back to the problem, we can use the sum of arithmetic series formula,

$y = x( \frac{z {}^{1} + {z}^{n} }{2} )$

Where x is the number of terms in our sequence. Z1 is the fist term of our series. ZN is our last term. And y is the sum of all of the terms

The first term is 5, the numbers of terms being added is 20 because 100/5=20. The last term is 100.

$y = 20( \frac{5 + 100}{2} )$

$y = 20( \frac{105}{2} )$

$y = 1050$

5 0

2 years ago

A prime number less than 100 is selected randomly. what is the probability that its square has units digit $7$?

liberstina [14]

Any number ends with 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9

Given any number. The square of this number is the last digit of square of the original numbers units digit.

For example

23*23 ends with 9 (3*3=9)

149*149 ends with 1 (9*9=81)

2564*2564 ends with 6 (4*4=16)

and so on

so all the possible unit digits of a square number are {0, 1, 4, 5, 6, 9}

because:

0*0= 0 ; 1*1=1; 2*2=4; 3*3=9; 4*4=16; 5*5=25, 6*6=36; 7*7=49; 8*8=64, 9*9=81

Thus, the probability that the square of a number selected from any set of numbers being 7, is 0.

Answer: 0

4 0

3 years ago