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

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18

v = 1/3 a^2h

step-by-step explanation:

if the height is 57.7cm and the height of the slant edge is 18.2cm, then the volume is 1/3 a^2h.