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Yakvenalex [24]
3 years ago
9

In a test, +3 marks are given for every correct answer and -1 are given for every incorrect answer (i) Sona scored +20 marks tho

ugh she got 10 correct answers. How many incorrect answers has she attempted??
Mathematics
1 answer:
e-lub [12.9K]3 years ago
4 0

Answer:

10 incorrect answers

Step-by-step explanation:

Correct answer = +3

Incorrect answer = - 1

Mark scored = 20

Number of correct answers = 10

Let:

Incorrect answers = y

Hence, we can fashion out the expression for total score :

(Number of correct answers * score per Correct answer + number of incorrect * score per incorrect) = total score

(10 * 3) + (y * - 1) = 20

30 - y = 20

-y = 20 - 30

-y = - 10

y = 10

10 incorrect answers

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Arturiano [62]

Answer:

If Length is decreased by 10% then it would become a square.

Step-by-step explanation:

Given:

Area of Rectangular field = 1440 sq. m

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Solution:

Let length be denoted by 'l'.

Also Let width be denoted by 'w'.

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l\times w = 1440 \ \ \ \ equation\ 1

Also we know that Perimeter of rectangular field is given by 2 times sum of  Length and width.

framing in equation form we get;

2(l+w) =152\\\\l+w =\frac{152}{2}\\\\l+w=76\\\\l=76-w \ \ \ \ equation \ 2

Now Substituting equation 2 in equation 1 we get;

l\times w =1440\\\\(76-w)w=1440\\\\76w-w^2=1440\\\\w^2-76w+1440 =0

Now we will find the root by factorizing the same we get;

w^2-36w-40w+1440=0\\\\w(w-36)-40(w-36)=0\\\\(w-36)(w-40) =0 \\

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So to find percentage decreased we will divide length to be decreased by total length and then multiply by 100.

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