0

options

3,5,2,6

my take

3y2 is divisible by 8 if y = 1 or 5 or 9

If y = 1, then


2094x84312 is divisible by 11 if x = 1


If y = 5, then


2094x84352 is divisible by 11 if x = 8


5x – 7y


If y = 9, then


2094x84392 is divisible by 11 if x = 4


For the largest possible value of x if x = 8 and y = 9


(5x – 7y) = 5 × 8 – 7 × 9 = 40 – 63 = -23

where am i wrong here ?

Bill Dubuque
  • 272,048
unknown
  • 37
  • you should use $y = 5$ and not $y =9$, when calculating $5x-7y$.... as when x = 8 , y= 5... so $58-75 = 5 $. this is because they have asked the value of y when x is the biggest. not the biggest values possible for both x,y – mrtechtroid Feb 04 '23 at 08:03
  • can we use y = 1 then ? why are we particularly taking 5 ? – unknown Feb 04 '23 at 08:08
  • Hi there, in your calculations you computed that x = 8 is the largest and this takes place when y = 5. So when you are computing 5x-7y, you need to take the value of y corresponding to x, which in this case is 5 and not (1 or 9).... – mrtechtroid Feb 04 '23 at 08:11
  • oh ok that makes sense thanks for clearing that up ! i am weak in maths so i dont really get it very quickly ! – unknown Feb 04 '23 at 08:13
  • Please delete the question now that all is clear, since it boils down to an oversight, so the question will not be useful to others (and may make browsingsearch results more difficult). – Bill Dubuque Feb 04 '23 at 16:49

0 Answers0