**6. Correct answer: (A)**

Given:

The figure

*r* = 50

To find:

*s* + *t* + *u*

Solution:

Topic(s): Pairs of angles

*s* + *t* + *u* = 50 + 50 + 120 = 220

**Answer: (A) 220**

**7. Correct answer: (C)**

Given:

Line *l *is perpendicular to the *y*-axis and passes through the point (5, -3)

To find:

The equation of line *l *

Solution:

Topic(s): Coordinate geometry

Line *l *is perpendicular to the *y*-axis.

This means it is a horizontal line (slope *m* = 0) that passes through the point (5, – 3).

The *y*-intercept will be at –3.

So, the equation of the line is *y* = – 3

**Answer: (C) y = – 3**

**8. Correct answer: (E)**

Given:

The profit obtained by selling *x *units is given by the function

*p*(*x*) = 17*x* – (10*x* + *b*), where *b *is a constant

300 units were sold for a profit of $1,900

To find:

The value of *b*

Solution:

300 units sold means *x* = 300

$1,900 profit means *p*(*x*) = 1900

Substitute into the function:

*p*(300) = 17 × 300 – (10 × 300 + *b*) = 1900

⇒ 5100 – 3000 – *b *= 1900

⇒ *b* = 2100 – 1900 = 200

**Answer: (E) 200**

**9. Correct answer: (E)**

To find:

The number that results when an integer is multiplied by itself CANNOT end in which of the following digits

Solution:

We need to eliminate the answers that are ending digits when an integer is multiplied by itself.

**Answer: (E) 8**

**10. Correct answer: (B)**

Given:

A bag with only red, blue and yellow marbles

The probability of selecting a red marble is

The probability of selecting a red marble is

To find:

The total number of marbles in the bag

Solution:

Topic(s): Probability

This means that the total number of marbles must be a multiple of 4 and a multiple of 6.

Check the answers to find the one that is a multiple of 4 and a multiple of 6.

**Answer: (B) 12**

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