To confirm (and presumably this would not be expected at 11+), you solve the simultaneous equations to find that oranges are 20p each and pears are 23p each.
I misread that as 'would be expected at 11+' rather than 'would NOT be expected at 11+' so I just worked it out to prove to myself that it worked. But then as it was just in a forum called Maths and we don't sit a maths 11+ paper here I didn't relate the question to the 11+. That might sound mad given that a month ago I could think of little else, but it is true! And finally, that is how my DS would work it out to confirm his answer.
Anyway, I'm sorry if my use of algebra alarmed anyone. I like daveg's solution, and hopefully this will make me think before I type again. (I'm relieved I got to the right answer though, it would have been even more embarassing had I not