Question

a student had multiplied a number by 4/3 instead of dividing it by 4/3 and got 70 more than the correct answer.find the number. the options are a)120 b)230 c)60. the wrong answer will be seriosly reported and the correct answer will be marked brainliest

Answer 1

Step-by-step explanation:

Let the number we want to find be 'x'.the student was supposed to multiply this number by 4/5.

So the correct answer should be (4*x)/5

But he accidentally divides the number by 4/5.

Now we know that dividing by a fraction a/b, (where a and b are not equal to 0) is equivalent to multipying by the inverse of the fraction, i.e multiplying by b/a.

So the student essentially multiplied the number by 5/4.

Now this value, you say, is 36 more than the correct answer. We are now ready to form our equation.

36 + correct answer = wrong answer

i.e 36 + (4x/5) = (5x/4)

i.e 36 + 0.8x = 1.25x

i.e 36 = 1.25x - 0.8x

i.e 0.45x = 36

i.e x = 36/0.45

Thus our mystery number is revealed, to be

x = 80.

Answer 2

Let the number we want to find be 'x'.the student was supposed to multiply this number by 4/3.

So the correct answer should be (4*x)/3

But he accidentally divides the number by 4/3.

Now we know that dividing by a fraction a/b, (where a and b are not equal to 0) is equivalent to multipying by the inverse of the fraction, i.e multiplying by b/a.

So the student essentially multiplied the number by 4/3.

Now this value, you say, is 70 more than the correct answer. We are now ready to form our equation.

70 + correct answer = wrong answer

i.e 70 + (4x/3) = (4x/3)

i.e 70 + 0.8x = 1.25x

i.e 70 = 1.25x - 0.8x

i.e 0.45x = 70

i.e x = 70/0.45

Thus our mystery number is revealed, to be

x = 80.