Variation

The cost c varies directly as the number n of pencils is written as

• $c=kn$

• $k=cn$
  

• 
  

  $n=\frac{k}{c}$

• $c=\frac{k}{n}$

The speed r of a moving object is inversely proportional to the time t travelled is written as

• $r=kt$

• $r=\frac{k}{t}$

• $t=kr$

• $\frac{r}{k}=r$

Which is an example of a direct variation?

• $xy=10$

• $y=\frac{2}{x}$

• $y=5x$

• $\frac{2}{y}=x$

A car travels a distance of d km in t hours. The formula that relates d to t is d = kt. What kind of variation is it?

• direct

• inverse

• joint

• joint

y varies directly as x and y = 32 when x = 4. Find the constant of variation.

• 8

• 36

• 28

• 128

What happens to T when h is doubled in the equation T = 4h?

• T is halved

• T is tripled

• T is doubled

• T becomes zero

If y varies directly as x and y = 12 when x = 4, find y when x = 12.

• 3

• 4

• 36

• 48

Mackee’s income varies directly as the number of days that she works. If she earns Php 8,000.00 in 20 days, how much will she earn if she worked 3 times as long?

• Php 26,000

• Php 24,000

• Php 20,000

• Php 16,000

If s varies directly as t and inversely as v, then which of the following equations describes the relation among the three variables s, t, and v?

• $s=\frac{k}{tv}$

• $s=\frac{kv}{t}$

• $\frac{1}{s}=\frac{kt}{v}$

• $s=\frac{kt}{v}$

What is your name?