Page 126 - Mathematics_Form_Two

Logarithms

(i) 2.5 × 10 1 (a) Hydrogen: 2.47 10 − 8 cm
(j) 9.18 × 10 5 (b) Oxygen: 3.39 10 − 8 cm
(k) 4.0 × 10 1 Represent the diameters in decimals.
(l) 1.06 × 10 2 8. A salon has 4 10× 2 clients in a month.

3. Evaluate each of the following If each stylist works 2.0 10× 2 hours
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per month, how many clients does
expressions and write the answers
Mathematics for Secondary Schools (a) ( 2.25 10 3 4 ) ( 4 10 ) (8 10   6 2 ) 9. A farm has 2.5 10× 2 acres which are
each stylist serve per hour if there are
in standard form:
4 10×
stylists? Give your answer in
1
standard form.
)
(b) ( 2.75 10
planted with maize. Each acre yields
3
1.2 10×
kg of maize. The farm sells
(c) (8.5 10
5
2.0 10×
kg of maize. How many
(d) ( 25 10 4 − ) (8 10 3 ) ( 2.4 10   4 ) 2 ) kilograms of maize are left?
(e) ( 222 10 − 3 ) (5.5 10  − 2 ) 10. A project requires 4.0 10× 7 bricks at
Tshs 1.5 10×
per brick. The project
3
4. Evaluate each of the following has a budget of Tshs 1.2 10× 8 . How
expressions, giving the answer in much money will remain after buying
n
the form A × 10 , where 1 ≤ A < 10 the bricks?
and n is an integer: 11. An intravenous drip delivers
9 10 4 7 10 6 2.0 10× 1 ml of fluid per hour for
(a) (b) 1
2 10 2 1.4 10 3 6.0 10× hours. If the patient needs
a total of 1.5 10× 3 ml of fluid, how
3 10 8 192 10 − 3 much more time is required to deliver
(c) (d)
5 10 8 3 10 − 2 the remaining fluid?

1984 − 8 3.5 10 − 2 12. A construction site has two steel
1984 10
(e) (f) beams. One weighs 3.2 10× 4 kg and
400 10 − 3 7 10 3 the other weighs 4.5 10× 5 kg. What
125 10 − 2 is their combined mass?
(g) (h)
5 10 2 13. A doctor prescribes to a patient a
dose of 2.0 10× − 3 g per day. If the
5. Find the area of a circle of radius patient has taken 5.5 10× − 4 g so far,
20 cm, giving the answer in standard how much more should the patient
form (use π = 3.142). take to reach the full dose?

6. The distance of the Earth from the 14. An earthquake releases 7.5 10× 18
sun is approximately 1.494 10 11 joules of energy. A smaller aftershock
kilometres.Write this distance in 17
decimal numerals. releases 2.0 10× joules of energy.
7. The diameters of certain molecules What is the total energy released by
have been calculated as follows: both events?

120
Student's Book Form Two

11/10/2024 20:12:49
MATHEMATIC F2 v5.indd 120
MATHEMATIC F2 v5.indd 120 11/10/2024 20:12:49