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sc practice math fun (1 Viewer)

Riot09

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i find it ironic that school certificate textbooks only contain the answers to question without any working out or explanantion,anyway heres just few questions that i dont get.any will you please provide working out annd an explanation below for the following questions.thank you

q.48.(a)jim borrows 12,000 for 3.5 years.interest is charged at $90 per month.

how much will he pay back in total?

the first thing i did was work out that 3.5 years equals to 24months then timesed that by $90 per month and added that total to 12,ooo which came to 14,160 in total and the answer is $3780, like wtf did read or misintrepet the question wrong?.

(b).if the interest is flat interest what interest is charged per annum?

q.51.a packet of chocolate is divided between sue,john and may in the ratio 5:2:1.if john gets 10 chocolates how many were in the packet?

the answer was 40 but the alternatives were 20,48 and 60.so my question is is there a way to do this question without using trial and error?

q.52. sue and simon buy a house for $150,000.they pay a deposit of $15,000 which they had saved and $7000,government grant,and borrow the remainder at a flat rate of 6% per annum interest for 15 years.how much interest do they pay?

q.56.(this one is a bit tricky) jane made 70 small cakes for the year 10 cake stall.if 35 were sold at $1 each and then 11 were sold when the price was reduced to 60c and a further 15 were sold when they were reduced to 40c each.
the remaining cakes were then shared between her friends.what was
the average price of her 70 cakes?

the answer is 68c but how?

q.58 tim and sonja are saving for a house.they have saved $21,000 for a deposit and that is 15% of the cost of the house.what is the cost?

Answer is 140k(again but how?)

q.66 thomas works 7 hours at $15 per hour then 2 and a half hours at time and a half (does that mean times by 1.5) and 1 and a half hours at double time.this means he will earn?
 

ninetypercent

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q.48.(a)jim borrows 12,000 for 3.5 years.interest is charged at $90 per month.

how much will he pay back in total?
90 x 3.5 x 12 = 3780

(b).if the interest is flat interest what interest is charged per annum?
umm dont really remember how to do this, but I think it's:

interest = 15780 - 12000 = 3780
3780 = 12,000 x r x 3.5
r = 9%

q.51.a packet of chocolate is divided between sue,john and may in the ratio 5:2:1.if john gets 10 chocolates how many were in the packet?
imagine the ratio as parts
John takes up 2 parts. he takes 10 chocolates. therefore, each part is 5 chocolates. There are 8 parts altogether. therefore, 5 x 8 = 40 chocolates
 
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ninetypercent

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q.52. sue and simon buy a house for $150,000.they pay a deposit of $15,000 which they had saved and $7000,government grant,and borrow the remainder at a flat rate of 6% per annum interest for 15 years.how much interest do they pay?
not sure I remember this, but I will try

remainder = 150, 000 - 15,000 - 7000 = 128 000
128,000 x 0.06 x 15 = 115,200

q.56.(this one is a bit tricky) jane made 70 small cakes for the year 10 cake stall.if 35 were sold at $1 each and then 11 were sold when the price was reduced to 60c and a further 15 were sold when they were reduced to 40c each.
the remaining cakes were then shared between her friends.what was
the average price of her 70 cakes?
35 cakes = 35 x $1 = $35
11 cakes = 11 x 0.6 = $6.60
15 cakes = 15 x 0.4 = $6

total money = 35 + 6.60 + 6 = $47.60
there are 70 cakes, so the average would be 47.60/70 = 68 cents



q.58 tim and sonja are saving for a house.they have saved $21,000 for a deposit and that is 15% of the cost of the house.what is the cost?
21 000 = 0.15 a
a = 140,000

q.66 thomas works 7 hours at $15 per hour then 2 and a half hours at time and a half (does that mean times by 1.5) and 1 and a half hours at double time.this means he will earn?
7 x 15 + 1.5 x 2.5 x 15 + 1.5 x 2 x 15 = 206.25 (which I think is wrong)
 

Riot09

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7 x 15 + 1.5 x 2.5 x 15 + 1.5 x 2 x 15 = 206.25 (which I think is wrong)

that was actually right.and you did all the questions.
 

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