# Mental Ability-Basic Arithmetic (NCO- Cyber Olympiad (SOF) Class 9): Questions 35 - 40 of 49

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## Question number: 35

» Mental Ability » Basic Arithmetic

MCQ▾

### Question

The bacteria in a culture grows by 20 % in the first hour, decreases by 10 % in the second hour and again increases by 20 % in the third hour. If at the end of the third hour the count of bacteria is 100000. The original count of bacteria in the sample is________

### Choices

Choice (4) Response

a.

129300

b.

129000

c.

129900

d.

129600

## Question number: 36

» Mental Ability » Basic Arithmetic

MCQ▾

### Question

Sterling gold is 92.5 % pure gold. How many grams of sterling gold must be mixed to a 90 % gold alloy to obtain a 500 gm of a 91 % gold alloy?

### Choices

Choice (4) Response

a.

100 gm

b.

50 gm

c.

150 gm

d.

200 gm

## Question number: 37

» Mental Ability » Basic Arithmetic

MCQ▾

### Question

Given, , and find the value of the following expression correct up to three places of decimal: .

### Choices

Choice (4) Response

a.

-17

b.

-12

c.

-10

d.

-30

## Question number: 38

» Mental Ability » Basic Arithmetic

MCQ▾

### Question

Divide 45 among four parts such that 2 added to first part, 2 subtracted from second part, third multiplied by 2 and the fourth divided by2 are all equal.

### Choices

Choice (4) Response

a.

5,8, 12,20

b.

8,12,5, 20

c.

12,8, 5,20

d.

20,5, 8,12

## Question number: 39

» Mental Ability » Basic Arithmetic

MCQ▾

### Question

Ifis factor of , find the value of a.

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 40

» Mental Ability » Basic Arithmetic

MCQ▾

### Question

The bacteria in a culture grows by 7 % in the first hour, decreases by 6 % in the second hour and again increases by 5 % in the third hour. If at the end of the third hour the count of bacteria is 11270000. The original count of bacteria in the sample is________

### Choices

Choice (4) Response

a.

b.

c.

11270000

d.

None of the above

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