Could someone help me answer this maths question ?

Question

Three pupils were asked to work out the value of 5x2 when x = 10.

Rob: 5x2 = 100 Sarah: 5x2 = 2500 Tamsin: 5x2 = 500.

Which pupil is correct? Explain why this pupil is correct. I put Rob but I don't know why becuase I guested. Is that right.

Answer 1

when x is 10, so the equation is like this..

5 ( 10 ) (2) =50 times 2= 100

Answer 2

Please! You must've been joking when asking this question!

Okay! Look: 5x2 is a another way of writing : 5*x*2

Therefore, 5x2=5*x*2  (where x=10)

=> 5x2= 5*10*2=100.

Well, other than that, 5x2 could also be another way of writing : 5*x^2

If so, then Tamsin is correct 'coz 5*10^2 = 500

Hope this helps.

Answer 3

Tamsin is correct

5 * x^2 = 5 (10^2)

5x2 = 5 times the square of ten. The square of ten is 100 then mulitply by the five to get 500

Hope that helps!

I've just noticed other peoples answers. I'm assuming because of the order of your question that it's 5 * (x^2) and not 5*x*2 because that would normally be written just 10x. Have a careful look at the question to see which it is.

Answer 4

= 5x²

= 5(10²)

= 5(100)

= 500

Answer: Tamsin is correct. 5x² = 500 where x = 10 as shown in the process of computation above.

Answer 5

The plane doesn't take off

Answer 6

It's really impossible to answer without seeing exactly what's written.

If the 2 (in 5x2) is a power (ie. smaller and to the top right of the x) then the equation is

5 x squared.

x=10, so you'd replace x with 10 and get:

5 multiplied by 10 squared  (ie. 5 multiplied by 10 multiplied by 10)

5 multiplied by 100 = 500

If the 2 isn't a power, then the answer's different and you need to repost the question.

Good luck!

Answer 7

I think Rob is correct because

5x2 = (5X2)x = 10X10 = 100

Tamsin would have been correct if the question was 5x^2

And I can't see how Sarah could have been correct.

Answer 8

You have to remember the rules of order of operations: PEMDAS

Parentheses, exponent, multiplication, division, addition, subtraction

Start with x2 (exponent): 10^2 = 100

Then multiply: 5 x 100 = 500

Tamsin is right.

Answer 9

yur correct well done

Answer 10

If X = 10, then 5X squared is 50 squared, which is 2,500

Answer 11

Rob is correct.

x

CinnamonGirl :)

Answer 12

all wrong the value is 5102 nobody mentioned multiplication! :)  

Answer 13

i would say rob 2.. bc since u mentioned that x= 10 .. u plug it into the equation 5x10=50x2=100. i think that would be how u do it..yea bc if u did it 50x20=10,000 so thats wasnt an option so i would say rob is correct with 100! good luck :D

Answer 14

Rob is correct.

Because 5 x 10 = 50

50 x 2 = 100

So it is Rob.

Answer 15

Rob is correct because

5x2 where x=10

5*10 = 50

50*2 = 100

Answer 16

All: 5x2 means is..

5 * x * 2, or 5 * 2 * x (since it doesn't matter in which order you multiply these)

5*2 = 10, so we now have

10 * x

We know that x = 10; so simply replace x with 10.

10 * 10 = 100

Hope this helps =)

Answer 17

Rob is correct ..

5x where x is 10

= 5*10

=50

then multiply by 2

=100