Question

) If the pattern shown continues, how many black keys appear on a portable keyboard with 49 white keys? Suggestion: use equivalent ratios or a rate table to confirm your answer.

Answer 1

Answer:

35

Step-by-step explanation:

Here we see 5 black keys for every 7 white keys.

So the ratio is 5:7

If we need 49 white keys, find the amount we scale the original ratio by:

    49/7 = 7

So we are scaling by a factor of 7.

The number of black keys would be 5 * the scale of 7. = 35

So there should be 35 black keys.

Answer 2

Using proportions, it is found that 35 black keys appear on a portable keyboard with 49 white keys.

• This question is solved by proportions, applying a rule of three.
• The equivalent ratio given, from the picture, is that for 7 white keys, there are 5 black keys. Hence, how many black keys will be there when there are 49 white keys?

The rule of three is:

7 white keys - 5 black keys

49 white keys - x black keys

Applying cross multiplication:

$7x = 49 \times 5$

Simplifying both sides by 7:

$x = 7 \times 5 = 35$

Hence, 35 black keys will appear.

A similar problem, also involving proportions, is given at https://brainly.com/question/24372153