5. Use the following instructions to find, in miles, the approximate
distances of the planets Mercury, Venus, Earth, and Mars,
respectively, from the Sun.
(i) Write down the series of numbers 0, 1, 2, 4.
(ii) Multiply each number by 3.
(iii) Add 4 to each of these answers.
(iv) Multiply each of these results by 9-3 million to obtain the
required distances.
Assuming that the planets move in the same plane in concentric
circles with the Sun at the centre, find how near to the Earth each
of the planets Mercury, Venus, and Mars can approach.
If the Earth completes a circle in 365 days, use the distance of the
Earth from the Sun obtained in (iv) to calculate its speed round the
Sun, to the nearest thousand miles per hour.
Take tt = 3T4.
6. A man is considering the investment of .£750 either in National
Savings Certificates or in 3|- per cent War Stock.
National Savings Certificates cost 15s each and at the end of 7 years
are worth 20s each. The War Stock is standing at 60.
Assuming that the War Stock remains at 60, find which of the two
investments would be financially better for the man by the end of
7 years, and by how much.
In fact he bought the War Stock but, on selling after 7 years, he
found that, with the interest, it gave him the same amount as the
National Savings Certificates would have done. At what price
was the War Stock standing when he sold ?
(You may use mathematical tables in Questions 7 and 8.)
7- (i) Evaluate ^/(9-24'2 + 8-532).
(ii) An athlete ran 100 yards in 10-3 seconds. Calculate his average
speed in miles per hour, expressing your answer correct to one
place of decimals.
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