Question

Li has t toy bricks.
She only has red bricks and blue bricks.
Li picks two bricks, one after the other.
If the first brick she picks is red, the probability that the second brick is red is
is 23
is 1 0
7
If the first brick she picks is blue, the probability that the second brick is red is
10
Calculate the value of t.

Answer 1

Probabilities are used to determine the chances of events

The value of t is 16

How to determine the probability

The number of bricks is given as t

Let the number of red bricks be x.

So, the number of blue bricks would be t - x

So, the probability values are:

$\frac{x -1}{t - 1} = \frac 13$ --- when the both bricks are red

$\frac{x}{t - 1} = \frac 25$ --- when only the second brick is red

Divide both equations

$\frac{x -1}{t - 1} \div \frac{x}{t - 1} = \frac 13 \div \frac 25$

Divide

$\frac{x -1}{x} = \frac 13 \div \frac 25$

This gives

$\frac{x -1}{x} = \frac 13 *\frac 52$

Evaluate the product

$\frac{x -1}{x} = \frac 56$

Cross multiply

$6x - 6 = 5x$

Collect like terms

$6x - 5x = 6$

$x = 6$

Recall that:

$\frac{x -1}{t - 1} = \frac 13$

So, we have:

$\frac{6 -1}{t - 1} = \frac 13$

$\frac{5}{t - 1} = \frac 13$

Cross multiply

$t -1 =15$

Add 1 to both sides

$t = 16$

Hence, the value of t is 16

Read more about probabilities at:

https://brainly.com/question/25870256