Question

Explain reasoning!

Answer 1

Answer:

1.) Incorrect,

2.) Correct

Step-by-step explanation:

1.) Let x be the amount of money,

After increasing x by 20%,

New amount of money ( say y )= (100+20)% of x ( i.e. y is 20% more than x )

= 120 % of x

$=\frac{120x}{100}$

⇒ y = 1.20x

$\because \frac{y-x}{y}\times 100=\frac{ 1.20x-x}{1.20x}\times 100$

$=\frac{0.2x}{1.2x}\times 100$

$=\frac{20}{1.2}$

≈ 16.67%

Thus, x is approximately 16.67% less than y.

2.) First score = 60%,

Second score = x% ( let )

So, Average percentage score = $\frac{60+x}{2}$

If $\frac{60+x}{2}=70$

$60+x=140\implies x = 80$