Shopper puzzle

Three items in a store are priced at USD 4.00   ,0.50    and,0.25
A person purchases 20 items paying a total of 20 dollars.
How many items of each did he buy?

Who paid for drinks

At one time the Canadian and US dollars were discounted by 10 cents on each side of the border i.e a Canadian dollar was worth 90 US cents in the US and a US dollar was worth 90 Canadian cents in Canada. A man walks into a bar on the US side of the border,orders 10 US cents worth of beer ,pays with a US dollar and receives a Canadian dollar in change.He then walks aross the border into Canada,orders 10 Canadian cents of beer,pays with a Canadian dollar and receives a US dollar in change.He continues this throughout the day, and ends up with the original dollar in his pocket.Who has paid for the drinks he has consumed?

Children weighing themselves-Rejoinder

This is a rejoinder regarding the issue of 5 children weighing themselves two at a time to reduce the ..expenses.The weights revealed by the weighing machine in ascending order were 51.7    52    53.5  54   55   55.3   55.8   56.7   57 and 58.5.You were asked to determine the individual weights
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If the individual weights were a,b,c,d and e the combinations 2 at a time possible are a+b,a+c,a+d a+e,b+c,b+d,b+e,c+d,c+e and d+e Adding all 10 values will result in the sum 4(a+b+c+d+e).So a+b+c+d+e=(51.7+52+53.5+54+55+55.3+55.8+56.7+57+58.5)/4=549.5/4=137.375.Deducting a+b=51.7 and d+e=58.5 we get c=27.175.We can then find that a=24.825,b=26.875,d=28.675 and e=29.825 

Conversation logic-Rejoinder

Since no one lies on Sundays and A says he does so in his second statement,it means he is lying.His first statement is also therefore false.Hence A lies on Mondays,Tuesdays and Wednesdays and B lies on Thursdays,Fridays and Saturdays.Since A and B do not lie on the same day,it means B is telling the truth.Since B lies on the next day as stated by him,the day of the conversation is Wednesday. 

Children weighing themselves

Five children thought of a scheme to weigh themselves on an automatic weighing machine at the cost of a single coin.Two of them got on to the stand at the same time,and one of them changed places with another until all the ten pairs are weighed..The results in kgs were as  follows-51.7..  52    53.5   54     55    55.3      55.8     56.7     57    and  58.5...What are their individual weights?

A Conversation logic

This is a logic puzzle for you
Out of 2 persons A and B,A lies on Mondays,Tuesdaysand Wednesdays and tells truth on other days.B lies on Thursdays,Fridays and Saturdays and speaks truth on other days.
At noon on a particular day the following conversation took place-
A-I lie on Saturdays
B-I will lie tomorrow
A-I lie on Sundays
On which day of the week this conversation took place?
  

Cryptogram for deciphering-Rejoinder

The sentence starts with  number 26.As A and I are the only single alphabet words,26 can stand for for alphabet   A or  I.By logic we can start the numbers 26,25,24 etc with A,B,C etc or I,J,K etc or I,H,G etc or A,Z,Y etc.
By seeing all these options we can decipher the sentence.It is actually as follows-
A bird in the hand is messy.,