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Electricity: 23.15 cents p/day plus 13.5 cents p/unit used Gas price: 24.5 cents p/day plus 5.5 cents p/unit used (a)(i) In 90 days, a family used 1885 units of electricity. Calculate the total cost, in dollars, of the electricity they used.

answer: $275.31(n of days x price p/day) + (n units used x price p/unit)(90 x 23.15) + (1885 x 13.5) = 27531 CENTS27531 CENTS = 275,31 DOLLARS

Answered by • Maths tutor

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The line l is a tangent to the circle x^2 + y^2 = 40 at the point A. A is the point (2, 6). The line l crosses the x-axis at the point P. Work out the area of triangle OAP.

The area of OAP is 60. The missing information I need is to find the x coordinate of point P. To do this I need to find the equation of the tangent. For this I first found the equation of the radius by fi...

Answered by Kai Y. • Maths tutor

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How do you know when to use sin, cos and tan?

When trying to work out and unknown angle in a right angled triangle, if you know the length of two sides you can use these the figure out the right trig function to use. SOH CAH TOA is an easy way to rem...

Answered by Emily D. • Maths tutor

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Completing the square of 2x^2 - 8x + 7 = 0

First divide everything by 2:x² - 4x + 3.5 = 0Then divide number in front of the x by 2 and put it in a bracket squared + x. Then outside the bracket subtract the halved number squared. Keep th...

Answered by Maria H. • Maths tutor

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Divide 711 in the ratio 4:5

Add 4+5 (which is 9)Tell them to divide 711 by 9 (=79)Multiple 79 by both values (79 x 4):(79 x 5)Answer is 316 : 395Explain that there is a way of finding out if they are correct. This is by adding 316 a...

Answered by Aini K. • Maths tutor

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