[racket] typo in HtDP

On Nov 29, 2011, at 6:55 PM, Bloch Stephen wrote:

> 
> On Nov 29, 2011, at 4:31 PM, David Van Horn wrote:
> 
>> On 11/29/11 4:28 PM, Jakub Hadam wrote:
>>> Hello,
>>> I claim there is a typo in the online version of HtDP:
>>> Exercise 4.3.3, the first condition should be
>>> 
>>> [(<=  n  1000) (*  .040  n)]
>>> 
>>> 
>>> 
>>> instead of
>>> 
>>> [(<=  n  1000) (*  .040  1000)]
>> 
>> Why?  That's what's in the printed book too and it seems perfectly reasonable to me.
> 
> Well, it's a "what is the value of this expression?" exercise, so technically it could have been anything.  However, to solve the intended problem of bank interest, Jakub is right: it should be (* .040 n) in the first case (otherwise people would earn the same $40 interest on a deposit of a penny as on a deposit of $1000.)
> 


The exercise is intentionally formulated this way. I am glad you discovered the twist. -- Matthias