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    Can someone PLEASE help me! I am currently doing a maths GCSE via open learning and i'm stuck on ratios. can someone help break this example question down for me really really simply?

    A man who smokes 15 cigarettes a day, finds that 24 packets will last him 32 days. If he cuts down to only 12 a day, and buys 18 packets, how long will they last?

    Number of cigarettes smoked per daydecreased in ratio 12:15 = 4:5
    (I understand this)

    Number of days they will last will increase in ratio 5:4
    (How do they come to this conclusion)

    Number of packets bought decreases in ratio 18:24 = 3:4
    (I understand how you get these figures too)

    Time they will last also decreases in ratio 3:4
    (I have no idea why this is?)

    Hence the time they will last = 30 days

    How can I work this equation out. This explanation is confusing me!

    Thanks

    Garrie:confused:
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    (Original post by garrierobert)
    Can someone PLEASE help me! I am currently doing a maths GCSE via open learning and i'm stuck on ratios. can someone help break this example question down for me really really simply?

    A man who smokes 15 cigarettes a day, finds that 24 packets will last him 32 days. If he cuts down to only 12 a day, and buys 18 packets, how long will they last?

    Number of cigarettes smoked per daydecreased in ratio 12:15 = 4:5
    (I understand this)

    Number of days they will last will increase in ratio 5:4
    (How do they come to this conclusion)

    Number of packets bought decreases in ratio 18:24 = 3:4
    (I understand how you get these figures too)

    Time they will last also decreases in ratio 3:4
    (I have no idea why this is?)

    Hence the time they will last = 30 days

    How can I work this equation out. This explanation is confusing me!

    Thanks

    Garrie:confused:
    Are you sure ratios are required here?

    I think the implication in the question is that if he smokes 15 a day for 32 days, he must smoke 15 x 32 = 480. If 480 cigarettes is 24 packets, that's 20 per pack. If he only buys 18 packets, in total that's 360 cigarettes. Smoking 12 a day, means that it would take him 30 days to smoke them all.

    The question does not contain ratios, so maybe you don't have to use them!

    Is that clear?
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    Of course he'd be better off not smoking at all, since there aren't any benefits...

    www.allencarr.com
 
 
 
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