Answer:
The equation of the relation ⇒ 
y = 18
Step-by-step explanation:
∵ y ∝ x/z
∴ y = kx/z
∵ y = 18 , x = 15 and z = 5
∴ 18 = 15k/5 ⇒ 18 = 3k
∴ k = 18/3 = 6
∴ y = 6x/z
∵ x = 21 and z = 7
∴ y = (6 × 21)/7 = 18
Only 20%of earths water is useable
The value of n in given proportion is 16
<u><em>Solution:</em></u>
We have to find the value of "n" in the proportion
<em><u>Given proportion is:</u></em>
<em><u></u></em>
<em><u></u></em>
We can solve the above proportion by cross-multiplying
Multiply the numerator of the left-hand fraction by the denominator of the right-hand fraction
Multiply the numerator of the right-hand fraction by the denominator of the left-hand fraction
Set the two products equal to each other
Solve for the variable




Thus the value of n in given proportion is 16
Answer:as likely as not
Step-by-step explanation: