Price Index

Dear Mr Moffat

I came across to below question for which I don’t understand and agree with the answer provided in the book
Could you kindly revise my working and point out the mistake if there is any?

Product M uses four different type of materials. The materials used and their prices in 2006 and 2007 are as follows:

2006
Material A kg 200 $0.98
Material B Kg 500 $ 0.95
Material C Kg 300 $1.20
Material D Kg 400 $1.10

2007
Material A kg 300 $1.40
Material B Kg 400 $1.10
Material C Kg 500 $0.92
Material D Kg 100 $1.14

Calculate the Laspeyre quantity index for 2007 (with 2006 as the base year) to two decimal places.

My working

As Laspeyre takes the base qty , where Paasque current qty.

2006
Material A kg 200 $0.98
Material B Kg 500 $ 0.95
Material C Kg 300 $1.20
Material D Kg 400 $1.10

Total 1471

2007
Material A kg 200 $1.40
Material B Kg 500 $1.10
Material C Kg 300 $0.92
Material D Kg 400 $1.14

Total 1562

1562/1471*100 106.19

Book answer

2006
Material A kg 200 $0.98
Material B Kg 500 $ 0.95
Material C Kg 300 $1.20
Material D Kg 400 $1.10

2007
Material A kg 300 $0.98
Material B Kg 400 $0.95
Material C Kg 500 $1.20
Material D Kg 100 $1.10

1384/1471*100 94.09

Since when do we need to use the price for the base year and not base qty to calculate the price index.

I think this is a mistake. Please correct me if I am wrong.

Thanks a lot for your help

Gabbi