9.3 × 107 would be the scientific notation
You just add the values for volunteers that worked 16-20 hours and 21-25 hours which would be 50 + 10 = 60. So the total number of volunteers that workers more than 15 hours is 60.

Let AB be a chord of the given circle with centre and radius 13 cm.
Then, OA = 13 cm and ab = 10 cm
From O, draw OL⊥ AB
We know that the perpendicular from the centre of a circle to a chord bisects the chord.
∴ AL = ½AB = (½ × 10)cm = 5 cm
From the right △OLA, we have
OA² = OL² + AL²
==> OL² = OA² – AL²
==> [(13)² – (5)²] cm² = 144cm²
==> OL = √144cm = 12 cm
Hence, the distance of the chord from the centre is 12 cm.
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Answer:
82/43 = 1 and 39/43
Step-by-step explanation:
When dividing 82 by 43 , the operation follows;
82/43 = 1 and 39/43
This means the quotient is 1 and reminder is 39
However;
82/43 = 1.907 ------nearest whole number is 2.
so the quotient can be approximated to the nearest whole number as 2.