How to Pass Numerical Reasoning (49 page)

Round the numbers to estimate the answer:

Complete the calculation:

Therefore, the rouble shows the largest percentage change.

Q4
a) 66

Using the percentage change formula work out the percentage change for the yen between August and September:

Now increase the koruna by the same amount. Work out 5% of 69:

Subtract 5% from the value of the koruna in August: 69 – 3.5 = 65.5. The question asks for an approximate answer, so select the answer closest to 65.5. Remember in currency conversion questions that when a currency
increases
or
strengthens
against the GB £, the amount of currency you receive for each pound decreases. The opposite is true when a currency weakens or falls.

Section 13 Gym membership

Q1
b) Kearns

Quickly calculate the cost of 5 months membership at each gym, remembering the minimum requirements for membership.

Even though Kearns requires a minimum 6-month membership, it is still less expensive to pay for 6 months at Kearns than 5 months at Hagen, which is the only gym to offer membership for less than 6 months.

Q2
e) None of the above

All the gyms are more expensive for monthly membership.

Q3
c) Hagen

Kearns and Deane are obviously less expensive than Doddington and Hagen, so eliminate these first. Hagen is more expensive per month than Doddington, but Doddington is closed for more days in the year, which increases the daily pro rata rate.

The question asks you for an approximate answer, so make a rough estimate of the correct answer by working out the total annual price of gym membership and divide by the number of days the gym is open in the year.

Doddington costs less than Hagen, so Hagen is the most expensive.

Section 14 Kishbek Semiconductor sales

Q1
e) 2000 roubles

In May, 500 4˝ wafers were sold. Total revenue for 4˝ wafers was 10,000 Kishbek roubles (Kr).

The price of one 4˝ wafer =

One 4˝ wafer costs 20 Kr and therefore 100 4˝ wafers = 20 × 100 Kr = 2000 Kr.

Q2
b) 100%

Sales of 6˝ wafers in May = 200.

Sales of 6˝ wafers in June = 400.

Recognize that if you double a number, you increase it by 100%. If this is not obvious, you can recall the formula for percentage change:

Q3
b) $156.25

First find the cost of one 6˝ wafer. Five 6˝ wafers cost 125 Kr, so one 6˝ wafer costs
¹²⁵
⁄
₅
= 25 Kr.

In May, 250 6˝ wafers cost 250 × 25 Kr = 6,250 Kr. In May, the exchange rate = 40 Kr : 1 US $, so divide
⁶²⁵⁰
⁄
₄₀
to find the $ price = $156.25.

In August, the exchange rate = 20 Kr : 1 US $, so divide
⁶²⁵⁰
⁄
₂₀
to find the $ price = $312.50.

The difference = $312.50 – $156.25 = $156.25.

Section 15 Energy tariffs

Q1
e) £40

There are two factors to consider in the calculation: (1) the cost of energy and (2) the daily service charge.

Energy consumed (2,854 kwh) × unit price (1.32p)

= approximately 3,700p.

+ consumption period (20 days) × daily charge (9.99p)

= approximately 200p.

3,700p + 200p = 3,900p or approximately £40.

Q2
a) £45

The price of electricity on tariff B = 102.5% × the price of electricity on tariff C:

Energy consumed (640kwh) × unit price (5.15p)

= approximately 3,300p

+ consumption period (91 days) × daily charge (13.39p)

= approximately 1,200p

3,300p + 1,200p = 4,500p or £45.

Q3
c) £7.50

To find total for energy on tariff A and tariff B:

Total for energy on tariff A and tariff B = 1,299p or £12.99.

To find total for energy on tariff C:

Energy consumed (250 kwh) × unit price (1.25p) + (120 kwh) × unit price (5.02p) + annual service charge (£11.50) = 915p + £11.50.

Total for energy on tariff C = £20.65.

The difference in price = £20.65 – £12.99 = £7.66.

The question asks for the approximate difference, so choose the answer closest to £7.66.