can anyone help with this maths question?

11 replies

wheelsonthebus · 22/12/2013 20:50

from a mock paper at 11+
Exactly how many minutes before six o'clock is it if, 50 minutes ago, it was four times as many minutes past three o'clock?
Dh and me are stumped (and he is quite good at maths...)

OP posts:

KristinScottThomas · 22/12/2013 20:57

talulahbelle · 22/12/2013 20:58

26minutes before 6

invicta · 22/12/2013 20:59

26 minutes. The time is 5.34. 50 minutes before is 4.44. That's 104 minutes after 3 pm. 104 divided by 4 is 26.

No, I'm not clever. I googled the answer. Not quite sure how you work it out.

lottysmum · 22/12/2013 20:59

25 minutes ...I think

talulahbelle · 22/12/2013 21:01

dammit, beaten! Well done kristin

Method -

From 1500 to 1800 is 4x minutes, 50 minutes, and x minutes, where x is the time to be found.

1500+4x+50+x=1800
1550+5x = 1800
5x=2hrs 10min
x=26min

Remember to work in base 60 (ie minutes) not base 10.

lottysmum · 22/12/2013 21:01

Drat out by a minute...

Ladymuck · 22/12/2013 21:03

50+4x=180-x
Add x to both sides
50+5x=180
Take 50 from both sides
5x=130
So x = 130/5=26

If child has done algebra then above would be the worked out answer expected, but I understand that state school children will be expected to use trial and error at this stage.

KristinScottThomas · 22/12/2013 21:03

Thanks, talulah. I always loved 11+ questions...

Original poster

wheelsonthebus · 22/12/2013 21:10

wow - i love mumsnet! thanks xx

OP posts:

PointyChristmasFairyWand · 23/12/2013 08:57

Ladymuck biiiiig assumption there. My state school DDs started algebra in Yr5.

(Not in a grammar area here though)

Ladymuck · 23/12/2013 10:36

Solely based on the L6 SATS marking scheme (which suggests that trial and error should be used for a surprising number of questions).

Flip