percentage change!! 幫幫忙丫`

Allan spends $8000on housing,$6000 on food,and $1000 on transportation each month.If his spending on housing and tranportation is in crease by 20% and 60% respectively,while the spendind on food is dreased by 8%,find his new total spending and the overall percentage change.(corr. ans to 4s.f. if necessary)

Housing
8000x(1+20%)
=9600
Transportation
1000x(1+60%)
=1600
Food
6000x(1-8%)
=5520
New total spend
9600+1600+5520
=16720
Origin total spend
8000+1000+6000
=15000
% change
16700-15000/15000x100%
=11.33%

2)In the cost of cigarettes,12.5% is on raw materials,37.5% on labour and 50% on advertisement.If both the meterial cost and labour cost are increased by 10% while advertisment cost is decreased by 5%,find the percentage change in the cost of cigarettes.

Let x be the total cost
raw materials
(12.5%+10%)x
=(22.5%)x
=0.225x

Labour
(37.5%+10%)x
=(47.5%)x
=0.475x

Advertisement
(1-10%)x
=0.9x

New cost
0.225x+0.475x+0.9x
=1.6x

Old cost
0.125x+0.5x+x
=1.625x

% change
1.6x-1.625x/1.625x‧100%
=-1.538%


you need to check it whether all answer are correct