Question

Theresa has an umbrella stand at the beach. - All of them are blue, except for six. - All of them are yellow, except for six. - All of them are red, except for six. How many blue umbrellas does Theresa have?

Answer 1

Answer:

3 Blue Umbrellas

Step-by-step explanation:

Given

$B \to Blue$

$Y \to Yellow$

$R \to Red$

From the question, we have:

$Y + R = 6$ ---- i.e. 6 are not blue

$B + R = 6$ ---- i.e. 6 are not yellow

$B + Y = 6$ ---- i.e. 6 are not red

Required

The number of blue umbrellas

Make B the subject in: $B + Y = 6$

$B = 6 - Y$

Substitute: $B = 6 - Y$ in $B + R = 6$

$6 - Y + R = 6$

Collect like terms

$R - Y = 6 - 6$

$R - Y = 0$

Rewrite:

$R = Y$

Substitute $R = Y$ in $Y + R = 6$

$Y + Y = 6$

$2Y = 6$

Divide both sides by 2

$Y=3$

Recall that: $B = 6 - Y$

$B = 6 - 3$

$B = 3$