<em>Word problem</em> is a topic that involves <em>interpreting</em> a given <u>statement</u> into a <em>mathematical expression</em>. Thus the answers to the question are:
1. r + 2 = 2r
r = 2
2. d = st
3. b = 4r
There are 9 red cards in the <u>pile</u>.
<em>Word problem</em> is a topic that involves <u>interpreting</u> a given <u>statemen</u>t into a <em>mathematical expression</em>. This often requires <u>representing</u> the <em>unknown</em> in the <em>statemen</em>t by an <u>alphabet.</u> So that the <u>value</u> that the <em>alphabet</em> represents is to be determined.
<em>Word problems</em> can be easily interpreted a <u>sentence</u> at a time. And it usually gives an <em>algebraic expression</em>.
In the given question, we have:
a) The sum of a number and two is twice the number.
Let the number be represented by <u>r</u>, we have;
r + 2 = 2r
So that by collecting like terms,
2r - r = 2
r = 2
b) Lorrae swims laps at a constant speed, s, for 2 hours.
The speed, s, of an <u>object</u> is the rate of the <u>distance</u> moved, d, to the <u>time</u> taken, t.
i.e speed, s, =
So that,
distance = speed * time taken
This implies that,
d = s * t
d = st
c) The number of black cards in a pile is 4 times the number of red cards. There are 36 black cards in the pile.
Let the <u>number</u> of black cards be represented by <u>b</u>, and that of <em>red cards</em> be r.
So that;
b = 4r
Given that b = 36, then;
r =
= 9
There are 9 <em>red cards</em> in the <u>pile</u>.
For more clarifications on word problems, visit: brainly.com/question/10731035
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