CIE Mathematics Paper-1: Specimen Questions 50 - 50 of 175

Question number: 50

Essay Question▾

Describe in Detail

Solve (9.122.35×3.06)2.47

(a) (i) Write the above expression with each number rounded to one significant figure.

(ii) Use your answer to find an estimate for the value of the expression.

(b) Solve the value of the original expression. Give your answer correct to 1 decimal place.

Explanation

Here,

(a) Here, expression is (9.122.35×3.06)2.57 .

Now, by rounding each number to one significant figure:

  • So, 9.12 will be 9 because after decimal point there is 1 which is less than 5, so 9 will remain same.
  • 2.35 will be 2 because after decimal point there is 3 which is less than 5, so 2 will remain same.
  • 3.06 will be 3 because after decimal point there is 0 which is less than 5, so 3 will remain same.
  • 2.57 will be 3 because after decimal point there is 5 which is greater than 5, so 2 will be rounded and be 3.

So, expression will be like: 92×33 .

(b) Here, answered expression after changing to one significant figure is: 92×33

  • So, it will be like: (92×3)÷3
  • So, as per BODMAS (Brackets, Order (Exponent), Division, multiplication, Addition, Subtraction) first of all we have to remove brackets and in brackets there are to calculations from which multiplication will take place first: (96)÷3.
  • Now, in brackets subtraction will be: 3÷3
  • At last, division will be: 1

(c) Here, original expression is: (9.122.35×3.06)2.57 .

  • So, it will be like: (9.122.35×3.06)÷2.57
  • So, as per BODMAS (Brackets, Order (Exponent), Division, multiplication, Addition, Subtraction) first of all we have to remove brackets and in brackets there are to calculations from which multiplication will take place first: (9.127.191)÷2.57.
  • Now, in brackets subtraction will be: 1.929÷2.57
  • At last, division will be: 0.751.

Now, correct it to one decimal place we will get: 0.8 because there is 5 after digit 7, which is greater than 5, so 7 will be rounded and be 8.

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