Question
Determine the following sum by using suitable rearrangement: $2 + 3 + 4 + 5 + 45 + 46 + 47 + 48.$
✓
Answer
Thus sum $2 + 3 + 4 + 5 + 45 + 46 + 47 + 48$ has to be evaluated using rearrangement.
We observe that,
$2 + 48 = 50 $
$3 + 47 = 50$
$ 4 + 46 = 50 $
$5 + 45 = 50$
Therefore $2 + 3 + 4 + 5 + 45 + 46 + 47 + 48 $
$= (5 + 45) (4 + 46) + (3 + 47) + (2 + 48) $
$= 50 + 50 + 50 + 50 $
$= 200$
Hence, $2 + 3 + 4 + 5 + 45 + 46 + 47 + 48 = 200.$
We observe that,
$2 + 48 = 50 $
$3 + 47 = 50$
$ 4 + 46 = 50 $
$5 + 45 = 50$
Therefore $2 + 3 + 4 + 5 + 45 + 46 + 47 + 48 $
$= (5 + 45) (4 + 46) + (3 + 47) + (2 + 48) $
$= 50 + 50 + 50 + 50 $
$= 200$
Hence, $2 + 3 + 4 + 5 + 45 + 46 + 47 + 48 = 200.$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Thirty students were interviewed to find out what they want to be in future. Their responses are listed as below:
doctor, engineer, doctor, pilot, officer, doctor, engineer, doctor, pilot, officer, pilot, engineer, officer, pilot, doctor, engineer, pilot, officer, doctor, officer, doctor, pilot, engineer, doctor, pilot, officer, doctor, pilot, doctor, engineer
Arrange the data in a table using tally marks.
doctor, engineer, doctor, pilot, officer, doctor, engineer, doctor, pilot, officer, pilot, engineer, officer, pilot, doctor, engineer, pilot, officer, doctor, officer, doctor, pilot, engineer, doctor, pilot, officer, doctor, pilot, doctor, engineer
Arrange the data in a table using tally marks.
Write the fractions in descending order.
$\frac{25}{16}, \frac{7}{8}, \frac{13}{4}, \frac{17}{32}$
→$\frac{25}{16}, \frac{7}{8}, \frac{13}{4}, \frac{17}{32}$
Parmindar walks around a square park once and covers $800m$. What will be the area of this park?
→Write the following ratios in the simplest form: $48$ min : $2$ hours $40$ min.
→Mark two points, $A$ and $B$ on a piece of paper and join them. Measure this length. Draw a line segment $CD$ that is: Half $AB.$
→Express the following ratios in the simplest form: $85 : 561$
→The school canteen charges $₹20$ for lunch and $₹4$ for milk for each day. How much money do you spend in $5$ days on these things?
→Find the sum of $(– 10), (92), (84)$ and $(– 15)$
→ In fig, line n is a transversal to lines l and m. identify the following: Angles alternate to $\angle\text{d}$ and $\angle\text{g}$ and angles corresponding to angles $\angle\text{f}$ and $\angle\text{h}$ in.
→ 
One out of two numbers is thrice the other. If their sum is $124$, find the numbers.
→