Lynn Byrd, Greg Byrd and, Chris Pearce Solutions for Chapter: Expressions, Formulae and Equations, Exercise 3: Exercise 2.2

A formula used in science is:

$V=IR$               where $V$ is the voltage

                                     $I$ is the current

                                    $R$ is the resistance

Find the value of $V$ when $I=4$ and $R=9$

A formula used in science is:

$V=IR$               where $V$ is the voltage

                                     $I$ is the current

                                    $R$ is the resistance

Find the value of $I$ when $V=30$ and $R=6$

A formula used in science is:

$V=IR$               where $V$ is the voltage

                                     $I$ is the current

                                    $R$ is the resistance

Find the value of $R$ when $V=40$ and $I=5$

Yola uses the formula $C=x+y$ to work out the total cost of tickets for an adult and a child to go swimming.

Arun consider the formula: I think $x$ is the cost of an adult ticket and $y$ is the cost of a child ticket.

Explain why Arun could be correct, but also why he could be incorrect.

Yola uses the formula $C=x+y$ to work out the total cost of tickets for an adult and a child to go swimming.

Arun consider the formula: I think $x$ is the cost of an adult ticket and $y$ is the cost of a child ticket.

How could you use Yola's formula to make it easier to use.

Mateo cuts a small piece of wire from a large piece of wire. He works out how much wire he has left using the formula $W=p-q$.

Sofia considers the formula.

I think that $p$ is the length of the small piece of wire and $q$ is the length of large piece of wire.

Is Sofia correct? Explain your answer.

Mateo cuts a small piece of wire from a large piece of wire. He works out how much wire he has left using the formula $W=p-q$.

Sofia considers the formula.

I think that $p$ is the length of the small piece of wire and $q$ is the length of large piece of wire.

How could you improve Mateo's formula to make it easier to use?

What value of $k$ can you substitute into these expressions to give you the same answer

$k+10\_\_\_\_\_3k\_\_\_\_\_20-k$