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On her first day in a hospital, Kiri receives u, milligrams (mg) of a therapeutic drug. The amountof the drug Kiri receives increases by the same amount, d, each day. On the seventh day,she receives 21 mg of the drug, and on the eleventh day she receives 29 mg.(a)Write down an equation, in terms of u, and d, for the amount of the drug that she receives(0)on the seventh day;

User Ashley Frieze
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1 Answer

27 votes
27 votes

Answer

The equation for the amount of drug received on the 7th day in terms of u and d is

a₇ = u + 6d

Step-by-step explanation

The description of the amount of drug administered on the first day and how the amount increases each day by d shows that this is an arithmetic progression question.

For an arithmetic progression with first term, u, and common difference, d, the nth term is given as

aₙ = u + (n - 1) d

a) So, for the 7th day

a₇ = u + (7 - 1) d

a₇ = u + 6d

Hope this Helps!!!

User Serpiton
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