Miss Lim bought some puzzles for her pupils in the Maths Club. She bought a total of 40 Tangram puzzles and IQ puzzles. She paid a total of $128. Each Tangram
puzzle cost $4 and each IQ puzzle cost $2. How many Tangram puzzles did she buy?​

She bought 24 Tangram puzzles

Step-by-step explanation:

Let the number of Tangram puzzles be t and the number of IQ puzzles be i

The sum of all the puzzles is 40;

i + t = 40 ••••••(i)

Cost of all Tangram puzzles at a cost of $4 per one will be;

4 * t = $4t

cost of all Iq puzzles at a cost of $2 per one is

2 * i = $2i

Sum

paid for all is $128

so;

4t + 2i = 128 •••••••(ii)

From equation i;

i = 40-t

Substitute into ii

4t + 2(40-t) = 128

4t + 80 - 2t = 128

2t = 128-80

2t = 48

t = 48/2

t = 24

the thermometer is precise but not accurate

step-by-step explanation:

step-by-step explanation: