A coffee shop blends 2 kinds of coffee, putting in 2 parts of a 33p. a gm. grade to 1 part of a 24p. a gm. If the mixture is changed to 1 part of the 33p. a gm. to 2 parts of the less expensive grade, how much will the shop save in blending 100 gms.

 Divide given quantity of coffee in 2:1 ratio which is equal to 2/3 and 1/3 1st case---cost for 1 gm coffee=(2/3 gm of 33p per gm)+(1/3 gm of 24p per gm) =(2*33/3)+(24/3) =22+8=30pcost of 100 gm =3000p=Rs.302nd case---cost for 1 gm coffee=(2/3 gm of 24p per gm)+(1/3 gm of 33p per gm) =(2*24/3)+(33/3) =16+11=27p cost of 100 gm =2700p=Rs.27so, shop saved 30-27=Rs.3